Somehwat interesting thread I saw the other day, which brought up this oft-discussed topic again. It seems this comes up frequently, but I have yet to get an answer that made sense to me without it immediately being contradicted by something that also seemed to have some logic behind it. Here's the most recent topic:
UJ pressure vs recoil thread

now, in the above case, it was brought about by a topic on chamber length. I'm NOT wondering about chamber length. I am wondering what exactly the effects of higher pressure are on a gun, independant of recoil; and also what the effects of higher recoil are in a gun independant of pressure. I have recieved contradictory advice from different doublegun smiths on the same shotgun before--one saying that just about any reasonalbe payload was fine so long as the pressure was low, and the other saying that any reasonable pressure was fine so long as the recoil was low...and then of course on the good 'ol intranets you get all sorts of technical information from people who seem like they know a little about a lot of things, and I have a hard time separating them from whose who are genuinely knowlegable. I'm sure this thread could become the same way...but in this case what I'm wondering is if there are any peer-reviewed references out there where a curious lad like myself could read up on this (without requiring a phd hopefully)? I'm hoping to find something that can explain in somewhat concrete terms what exactly the real affects of both pressure and recoil are on the various parts of a gun, what the consequences are of varying levels of each, what the thought process is behind the various standards, some info on proof testing of guns and its purpose, etc. I tried accessing some of the publications on the SAAMI website but they repeatedly froze my computer. Is there an equivalent CIP website or reference that I might look for? I know of a couple books already that I'll look for, but what are the key ones? Other info? Is there a "Bat-signal" that Sherman Bell responds to?
Thanks,
Dave

I'd have to agree with the above...no concrete evidence, it just makes the most sense.

What most of us perceive a "recoil" is a result of the spike that occurs. Basically, felt recoil is measured by the peak measurement desribed by force against your shoulder. Essentially, it's the differnece between a gentle push against your shoulder, versus a punch. Both have that same total energy, but one feels more comfortable. All other things being equal, that's why a load with slow burning powder will feel less "pushy",and today's promotional loads which generate more pressure, and therefore higher recoil and worse patterns

Pressure blows apart barrels, recoil breaks stocks. That is if you talking only the effect on the gun. If you can afford to replace stocks don't worry about recoil. Loosing your fingers or eyes is a different thing all together, of course. All depends on what gun your talking about? Remington 870 - no worries, unless your have mud in the bore.

SAAMI 1931

A couple of things must be understood. Pressure & Recoil are not directly related in the way many assume. Heavy recoil can be generated with low pressure & High pressure may generate low recoil.
Ben-T pretty well has it summed up. Pressure is of concern primarily to the chamber of the gun,ie wall thickness in that area. Frame flexing, stock cracking etc are all dependant on the recoil.
Charge wt and/or velocity determine recoil. Powder burn rate vs charge wt determine pressure.
Incidently there are dangers involved with pressures being either Too high or "Too Low". Any gun I do not feel comfortable using loads of up to 8K psi, I hang on the wall.

Does that help and do you have remaining questions.

Glad someone brought up this discussion over here. The main issue in the discussion over on UJ is whether overpressure (for example, using modern American factory loads in either American or foreign guns, made with shorter chambers and proofed at lower than current standards, and designed for lower service pressure) will accelerate wear--as in causing a gun to shoot loose (off face) sooner? I contend that pressure is the primary issue here, not recoil.

Rocketman, I'm having trouble matching up your "quote" with 2 Piper's post just above it. Looks like either he edited his original post, deleting comments about accelerated wear to metal parts, or else that was your addition to his post and somehow got included in the quote.

Having followed a lot of these discussions on this BB for a number of years, it seems to me that the consensus has always been: pressure can cause catastrophic failures and accelerate wear of metal parts; recoil mainly impacts the stock (and the shooter).

Ben-T and Rocketman I appreciate the brevity of your responses and totally agree with your statement but by extension could we also say that since we are discussing the effects of heavy recoil on a double gun that excessive recoil induces additional wear on the barrel lug, hinge pin, under bites and other locking mechanisms and prematurely wears or cause damage to these parts in addition to breaking stocks?

Pressure


Recoil


Pete

Oil soaking didn't help that stock. ;-)

Larry, I edited to set my comments apart in red. Also, yes, I went further into wear to locking parts and attributed this to pressure rather than recoil.

Post back if it is still not clear.

So, higher pressure will increase wear on the hinge pin, more than increased recoil will?

The picture I posted above is from a 1931 article about the establishment of SAAMI. I thought it was pertinent to this discussion because you see that it is set up to measure pressure, recoil and velocity.

Since all have been mentioned in this discussion and at UJ I thought I would show that SAAMI recognizes the interrelation of the three and has from the time SAAMI was established.

Recoil per se doesn't exist within the gun since the barrels and stock are locked to the action. However, there is a force transmission to any object interfering with the free recoil of the gun. The weak point in the force transmission from the action to the butt is at the stock head and wrist. If the recoil force is too high, you can literally split the wood. And, if the stock develops any looseness, you will get battering of the wood. We would be more correct to say the stock is damaged by transmitting recoil force.

Wear to the hinge pin/hook during firing can occur from battering or relative movement. Battering occurs where there is a bit of off-face so the hook gets a run at the hinge pin. Any strain movement between the hook and pin will result in surface grinding. The action will bend slightly during firing and this changes the position of the hook relative to the pin; maybe only a fraction of a degree, but enough that there is movement. Clean, high pressure lube will minimize metal to metal contact and fine particle grinding, but can't completely eliminate it. Tight on-face, along with hard surfaces on the pin and hook minimize battering.

Let me know if that is not clear.

Not perfectly clear, especially when I try to reconcile this post with the earlier statement...

"Larry, I edited to set my comments apart in red. Also, yes, I went further into wear to locking parts and attributed this to pressure rather than recoil."

Which seems to exclude recoil as a source of wear to locking parts.

You say "recoil force doesn't exist within the gun..." and later in the same paragraph refer to "battering of the wood" and the crux of the paragraph seems to say that "transmitted recoil force batters the wood."

Your second paragraph covers "movement, grinding, and battering" (metal wear) without using the word "recoil."
Is or,is not, this movement, grinding and battering of metal parts "within the gun" due to the same "transmitted recoil force"
that batters the stock?

Is it not true that it is recoil force transmitted to poorly mated metal surfaces that causes their grinding, battering, loosening, i.e.; wear?

If not, then it's CHAMBER PRESSURE and NOT RECOIL that causes the pin and hook to be battered? Clear as mud.

I am also having trouble reconciling those statements. First no recoil then where does the battering come from? Just how does that happen and how is it pressure related since recoil is generated as per Newtons 3d law of motion and no matter how you calculate it pressure plays no direct part in producing recoil?

For your information or a reminder the following is the formula for calculating recoil:

E= 1/2(Wr/32)(WbxMv+4700xWp/7000xWr) squared

E= energy in foot pounds
Wr= weight of gun in pounds
Wb= weight of whot and wad
Mv= muzzle velocity in fps
Wp= weight of powder in grains


You will plainly see there is no element called pressure.

Lastly in your reply to Larry brown you state "Larry, I edited to set my comments apart in red. Also, yes, I went further into wear to locking parts and attributed this to pressure rather than recoil."

How does pressure which is totally contained withing the chamber and barrel act of the locking parts without any direct contact?

I'll stick with the pre-Rocket "pretty well" summation by Ben and Pipes. Little bitty ejecta go one way damn skippy; big ol gun don't come back all that fast but since it's usually about 96 times as heavy as ejecta it comes back for real no matter how you "perceive" the event. That's a Newtonian moment; it's equal and oppo; it's recoil. All that business from Rocket about battering and hammering and is the gun "unitized" thru the stock head, etc. is fine but recoil is sufficient as an immediate cause. Pressure may be the primum mobile in putting a lot of expanding gas between piston and cylinder head but all that stuff moving is enuf to explain mechanical wear without introducing Caspar the unfriendly ghost in the machine.

jack

Rocketman, thanks. Thought maybe the additional comments were yours, but wanted to be sure.

SAAMI lists available loads for the various gauges, including shot charge and velocity (which are the most important elements in recoil). However, if we look at what's happened in the shotshell world over the last few years, we can see that recoil has increased significantly--especially because there are now much higher MV lead loads out there than in the past. (I pattern tested some 12ga, 1 1/4 oz 1500 fps loads. Ouch.) In spite of those increases in recoil, the standard established by SAAMI remains focused on pressure. That is to say, as long as those loads fall within the acceptable service pressure ceiling of 11,500 psi, they're good to go with SAAMI. Seems to me that, assuming recoil threatens the integrity of a gun--even cumulatively, over time--SAAMI would establish some sort of recoil ceiling as well, limiting maximum shot charge and velocity. The fact that they have not done so indicates to me that they consider recoil of any load that falls under their service pressure ceiling to be a non-issue for any shotgun that passes current SAAMI proof (19,000 psi, for 12 and 16ga). Yet obviously, since the standard they set is one of pressure and not recoil, they don't consider pressure to be a non-issue.

If a shotgun were held dangling on a string, and a cartridge fired, what would it do? It would accelerate equally and opposite to the cartridge ejecta.
As one piece, bound inseparably.

Let me put this more bluntly.

Assume I have one shotgun. It's old. It's in good shape, but it's 100 years old.

Walking along one day i come to a fork in the road.

On the right fork is a greasy guy with slicked-back hair and a truckload of ammo that reads:
calculated recoil=almost zilch
Chamber pressure=SAAMI Max
This guy tells me that if I take his fork in the road, I can have his truckload of ammo to shoot my gun to my hearts content.
WHAT WILL HAPPEN TO MY GUN IF i TAKE THIS ROAD AND SHOOT MY GUN TO MY HEARTS CONTENT??

On the left fork, is another guy--dressed in somewhat unfashionably old clothes and smoking a pipe--with a wagonload of ammo that reads:
calculated recoil=hope you have a heavy gun with a thick recoil pad
chamber pressure="It's a miracle, but nice consistent ignition in any weather, 500psi (yes, five HUNDRED psi)"
The guy tells me that if I take the left fork I can take the entire wagonload of ammo to shoot my gun to my hearts content.
WHAT WILL HAPPEN TO MY GUN IF I TAKE THIS ROAD AND SHOOT MY GUN TO MY HEARTS CONTENT??

Assume my stock wood is just fine and the recoil is a non-issue ot the shooter, I'm only concerned about the gun or any issues caused by the gun. Which road is better for my gun? Which road will cause my gun to "shoot loose" faster assuming it's well-maintained in all other respects? Why? What are the best books or references that might help one learn about this in order to make my own decisions?

Pressure blows out the barrels almost instantaneously. Your gun would be beat to pieces more slowly.
The pressure to pop the barrels is high instantaneous psi, whereas recoil is in momentum units.
Maybe rocketman can clearly explain radial pressure versus time and overlay it on a recoil vs time graph. One happens before the other, in a perpendicular direction to the shotgun holder.

I have seen the figures for chamber pressure of the lowly .22LR rimfire, but do not have them handy now. I seem to recall they were at least approaching the 20K psi range. This is far above the the max allowable SAAMI pressures for even a modern 3½" 12ga Mag, yet I do not recall anyone ever mentioning "Shooting a gun Loose" from using one of the .22LR insert bbls fitted to a shotgun bbl, nor splitting a stock. My original post may not have been "Technically" correct, but in laymans terms I do believe it to be 100% correct. To figure the strength of a tube the important consideraation is pressure. To calculate frame strength, stock strength etc the important consideration is "Back Thrust" what ever terms you want to call it. Most looseness in break open shotguns is the result of frictional wear from improper maintenance & lubrication.
While certainly pressure is a contributing factor the "Back Thrust" is a combination of the pressure over the area it pushes against & the factor seldom mentioned of time.
I can fire a 2½" .410 with ½oz of shot @ 1200 fps & attain 11K psi. I can fire a 12ga 3" with 1½oz shot @ 1315 fps with 10.7K psi both using Hercules/Alliant 2400 powder. Assume both of these loads fired from guns having same stocking, same strength of frame etc, etc & I do not by the most elaborate of imagination believe I really have to ask anyone here which load would put the most strain on that gun. If you want to determine what load will come the nearest to "Shooting a Gun Loose" calculating the recoil of its load will be far more meaningful than will its chamber pressure. Incidently both of the above mentioned example loads were taken from an Alliant Manual & used Rem Hulls & Rem Wads. I hand-picked them for "Close" pressures but with any difference being for higher in the smaller .410.
I could just as easily point to 2 3/4" 12ga loads of 1oz/1200fps vs 1¼oz/1330fps; both @ an identical 9,500 psi. the lighter load simply "Will Not" "Shoot the Gun Loose" as quickly as will the heavier one even though both have an identical chamber pressure.
"I Rest My Case"
Do understand of course, the chamber pressue must be within the limits of what the chamber walls can take. I would certainly not recommend shooting an olg gun with thin chamber walls with ammo having pressures approaching SAAMI standards regsrdless of how light the recoil. If we look to extremes with a fast enough powder bursting pressures could be reached while producing almost no recoil as the pressure could rise so fast virtually no movement of the shot would have taken place while the pressure escaped out that big Gaping hole in the chamber side. The stock would of course be intact.

Gotta be careful where you attach that ONE string. Might get some sort of pinwheel rotation about a single center and a barrel dent, or heaven forbid, a stock ding. And gun sure as hell wouldn't accelerate at the same rate (relative "steepness" of plot for you math sophisticates--you know who you are) or to a maximum velocity equal to that of the ejecta. Mass x Distance / Time still balances both sides of Mr. Equal Sign.

jack

This is confusing...

Say you have two shells one is high pressure and one is low pressure both are 1 & 1/4oz. 12 ga. loads.

How is the higher pressure shell going to kick less than a low pressure shell ?

...and the engineer said "you can't do that. That violates the laws of physics." The politician says "that's what we're here for, to change the law".

This certainly sounds like recoil--not pressure--is by far the bigger gremlin, at least when it comes to wear and tear on the action of a gun. Is that fair to say?

I am curious about the second part of the observation though.



Given that I shoot very mild-recoiling loads (mostly 7/8oz <1200fps), what would be the difference to a gun between shooting a lot of 7000psi loads vs the same quantity of 11000psi loads? How would this likely manifest itself in the gun? I ask because it seems a matter of degree--my assumption is that at some point the pressure becomes "too much", and that's the working pressure the gun was designed to handle...but I assume it won't burst if I exceed that by just a little ("a little"=11k psi is still less than the gun was proofed at), so is any damamge likely to happen at all, is it likely to be cumulative, how will it manifest itself? Will this gun shooting 11000psi loads "shoot loose" faster than if I were using the 7000psi loads? Will any additional damage (i.e. the damage above what you would get from the lower pressure loads) be largely confined to the barrels, or would it encompass all of the action parts as well?

When we speak of pressure here we are speaking "Only" of the peak maximum pressure. The higher pressure shell is going to "Kick Less" only if it has a lower velocity. Again turning to my trusty Alliant manual I find these loads; A 3¼DE load with 1¼oz shot at 1220fps having a max pressure of 10,300psi with 23 grains of powder X. Using same hull, same wad & same primer I can change to powder Y & give that same 1¼oz of shot a 3½DE, 1275 fps, using using 34grains of this slower powder @ a max pressure of only 8,600psi. Since this load is scheiving 55 fps more velocity it would Kick Harder even though having a peak pressure 1700psi lower. "If" however you had a pressure gun which measured the "Entire" pressure curve, you would find that even though it has a lower peak, its average pressure under the entire curve would be higher. That lower peak will be offset by a higher pressure down the remaining length of the bbl.
The answer to your question is really very basic balistics. The recoil is based on the total wt of what goes down the bbl; shot, wads & powder & the velocity they attain. The pressure is based on the burn rate of the powder vs the wt it lifts (pushes down the bbl). A faster powder can reach a higher pressure while attaining a lower velocity & thus a lower recoil.
In the above example the 55fps extra velocity would more than offset the 11 grains wt of extra powder to be pushed out the bbl in the form of gases. This is about a 4.5% velocity increase with only a 1.8% wt increase. Pressure does not enter into the formula for calculating recoil at all, only motion & wt.

David;
When figuring the strengths of steel there are several factors which are involved. The two which holds the most interest to us here are Ultimate tensil & yield tensil, some times referred to as the elastic limit. The ultimate is of course the point at which the steel will break or in our case burst. The yield is the point at which it will accquire a permanent bulge. When pressure is applied inside the chamber it will "Swell" slightly, but upon removal of the pressure will return to original size. pon the pressure reaching the yield strength it will immediately take a sudden increase in its "Swell" & will not return to original size upon removal of the pressure, thus bulge has resulted. If the pressure is high enough it will of course continue to swell until it reaches the bursting point. Now lets assume that by knowing the yield strength of the steel we could then calculate that the pressure required to stress a given chamber to its yield point was 12K psi. "Theoritically" then we could fire a million rounds @ 11K psi with no detrimental effect. However another factor rears its Ugly Head, this may not be the correct technical term, but we have to consider the "Fatique Factor". This is simply saying if we go too close to the limit for too many times eventually the steel will just "Get Tired" & fail even though we never actually reached its failure point. This is of course one of the major reasons why service pressure is only a fraction of proof pressure. The best advise I can give is to simply keep ones loads within the service pressure for which the gun was designed.

I agree with all of your statements concerning recoil and pressure and their effects on the gun, Miller. And, as far as "calculating recoil" goes, with the above statement, too. Calculations, however accurate, do not totally agree with what I perceive the recoil to feel like. And, to take it one step further, and to parlay it into a partial answer to David's question as to how it affects his gun, I think burn rate of powder and the resulting "sharper" pressure spikes resulting from faster burning powders' use (read promotional loads here), also deliver a "sharper" blow to my shoulder, but more importantly to the head of the wood stocked gun. Even though the calculated ft.lbs. of recoil may read the same on paper.

A black powder load pushing 1 1/4 oz. of lead at 1100 fps will not feel nearly as "punchy" to me as a very fast burning smokeless load of the same weight and velocity out of the self same gun. I know you must have felt that difference as well. I believe that "sharpness" of recoil, i.e., the same calculated recoil delivered in a shorter time span will deliver more punishment to the wood at the stock head. Agree?

Truth be known though, that difference may be lost on a well inletted stock head and a piece of very dense and dry wood. If not lost totally, the differences in damage to the wood may, or may not, be incalculable.

Stan the problem with quantifying perceived recoil is that it depends upon very subjective evaluation on the part of the individual experiencing the recoil event. As you know no two human nervous systems are exactly alike so what may be perceived by a strapping young fellow as mild recoil may be perceived by an old duffer such as myself as a sever recoil event but after taking a couple Alievs I might find the same recoil impulse to be only moderate.

I'm using red text for my answers to try and keep question and answer close together. DF, I'm answering your specific questions only here. General answers will follow.

Mike, I'm inserting answers into the quote in red to help keep Q & A close, yet separated.

What we're neglecting here, I think, where pressure is concerned is that a burst is not the ONLY possible negative result of shooting overpressure loads. That's the "shade tree gunsmith" view of proof: Work up a heavy load, put it in the gun, secure the gun to a tire, tie a string to the trigger, and go hide behind a tree. If the barrel doesn't burst or the gun otherwise fly to pieces, you're good to go. But that's not the way proof is done by the proofhouses. They also do something called "view" or "inspection", measuring for minute changes that may have occurred after firing--even if the barrels are still intact. If proofloads--which are, obviously, far in excess of service pressure--can cause such minute changes without resulting in catastrophic failure, than why cannot a SAAMI max load of 11,500 psi also cause minute changes (especially if used thousands of times) in a gun with a designed service pressure of 9,500 psi? If pressure is not an issue but recoil is, then that means I'm better off shooting a 1 oz load using 18.5 grains of Red Dot in an STS hull, 10,900 psi/1255 fps (courtesy of the Alliant book) rather than a 2 1/2" Eley Hawk VIP Game, 1 oz, 1300 fps--the latter producing higher recoil because of the greater velocity (but loaded to the lower CIP service pressure standard).

I think we also need to remember, especially as we approach SAAMI max service pressure (as in the above example) that although many of the loads Sherman Bell tested in his DGJ article showed a pressure increase of only a few hundred psi when fired in a short chamber, others approached (and at least one even exceeded) an increase of 1,000 psi. Factor in the variation from one reload to another, you could end up well over SAAMI max service pressure--and, worst case, not that far below original proof pressure of an older shotgun. (Which is why it's a very good idea to err on the side of caution when reloading for vintage guns. Fortunately, that's very easy to do for the 12ga in particular.)

Ok, I'm going to throw my $.02 in....

I haven't seen anything mentioned about powder burn rate. Assuming equivalent payloads and velocities, I would expect that a faster buring powder would create higher peak pressures. My rationale is this: Pressure is created by expanding gases. If the area the gas expands into is larger the pressure will be less. With a slower buring powder the "ejecta" starts moving down the barrel as pressure increases thus increasing the expansion area and resulting in a lower peak pressure. I would also expect the "felt" recoil with a slower buring powder to be less for similar reasons.

Phil

[quote=L. Brown If pressure is not an issue but recoil is, then that means I'm better off shooting a 1 oz load using 18.5 grains of Red Dot in an STS hull, 10,900 psi/1255 fps (courtesy of the Alliant book) rather than a 2 1/2" Eley Hawk VIP Game, 1 oz, 1300 fps--the latter producing higher recoil because of the greater velocity (but loaded to the lower CIP service pressure standard).
[/quote]

Yep. Correct. Exactly!

Although your example is not the finest, beacuse the free recoil energy is a trivial 6% different between the two.


Here's a better example right out of your Alliant data...

1 ounce @1250 fps, pressure 10,900 psi

1 3/8 ounce @ 1250 fps, pressure 7,800 psi

Which one would is better for your 7 lb doublegun, Larry?

High pressure and 17 ft lbs of recoil or loooooooww pressure and 36 ft lbs?

You've professed respect for Miller's expertise; here's his take again....

"I could just as easily point to 2 3/4" 12ga loads of 1oz/1200fps vs 1¼oz/1330fps; both @ an identical 9,500 psi. the lighter load simply "Will Not" "Shoot the Gun Loose" as quickly as will the heavier one even though both have an identical chamber pressure."

Good question, Mike.

First of all, I don't like 1 3/8 oz in a vintage 12ga, because the max load available in my 1940 Shooters Bible for the 2 3/4" 12ga is 1 1/4 oz. Assuming we're talking a gun with original short (2 5/8", in the 12ga) chambers, which was the genesis of this discussion, heaviest load available for those was 1 1/8 oz. Thus, I interpret that load as being inappropriate for the gun--certainly for the stock, if not for the metal--and seriously inappropriate for the guy on the butt end of the gun.

However, I'd also avoid the 1 oz load like the plague. Add in a little extra pressure because of the too long hull, maybe a little more because my reloader dropped a little too much powder--I'm over current SAAMI max pressure. And way over max pressure for a gun built with short chambers.

In other words . . . two bad choices. And while I appreciate Miller's expertise, I also appreciate Rocketman's. And the fact that both SAAMI and CIP focus on PRESSURE standards, not RECOIL standards. That in spite of the fact that recoil has increased significantly with modern loads--some of which pack 1 5/8 oz of shot into a hull that, back when those vintage guns were built, contained a maximum of 1 1/4 oz. (That's half an ounce more than was offered in the short 12ga hulls--at the same velocity of 1250 fps that the maximum 1 1/8 oz load achieved in the 2 5/8" hull.) With all that additional recoil (but note, still within SAAMI pressure standards) . . . why aren't our modern doubles shooting loose, if that's what happens as a result of recoil?

Thanks, but I don't think you could explain it so I can agree.

Recoil is the movement of the gun, which is the sum of its parts. And it is recoil of these independent parts that accelerates wear on both wooden and metal parts.

Many posters seem to readily accept that it's the recoiling barrel/action assembly as a unit which traverses a few thousandths gap and slams into the immovable object, which is the stock head and imparts damage to the wood.

Yet these same posters cannot accept the fact that it is the recoiling frame being thrust backwards over a few thousandths gap and slamming into the immovable object, which is the hook welded to the barrels, that imparts damage to those metal parts.

Pressure is a necessary condition for the generation of recoil, but is insufficient for quantifying it. And while high pressure without recoil can wear/fatigue/rupture the chamber, it cannot induce greater wear on moving parts (hinge/pin/stock head) except to the extent that it imparts higher recoil energy to those parts.

I can't explain it better than that.

Gee, I don't know, Larry.

Maybe it's because Sarasquetas and Huglus are built so much better than my 1920's Foxes?

TwiceBarrel, You are absolutely correct in your stated question! My thinking on the effect of these two forces on an OLDER gun may have been limited to the current and future use of the gun rather than it's past use. Assuming an "older" gun was used extensively with heavy shot charges and pressures common in the years following its' manufacture, recoil most certainly could have an effect on all parts you mention. If this were the case I would think that wear would show now, but perhaps not? In terms of current use of and older gun, appropriate ammunition should be used to prevent or minimize wear. Of couse most things that get used, even appropriately, wear. Speaking only for myself, my statements on pressure and recoil should be taken merely as a warning as to the possible result that could occur if some caution is not taken when choosing ammunition for a shotgun that may have been manufactured when lower pressure shells were used, but also keeping in mind that older wood may break and can be exspensive to replace.

Mike Campbell is getting real close to the bottom line, using both sarcasm and engineering knowledge to reach the goal. He knows that fit and battering are the only things we have to worry about unless our barrels blow up. Guns that were made last year don't normally succumb from battering, even Huglus. Guns that are designed and fit well don't normally succumb from any normal use, even heavy use of high pressure or heavily loaded ammunition. His sarcastic mention of the Fox refers to the fact that a Fox, properly bolted and lubricated, will put up with decades of heavy use without the negative results of battering. I own a Parker shotgun that has been abused with many thousands of rounds of heavy recoiling ammunition over eighty plus years, but it shows no sign of battering because it has always been kept tight. Looseness is the prime cause of wear caused by battering. If a good gun is kept tight and lubricated, battering is just not a factor in wear. Further proof that a well designed tight gun prevents signs of battering is in the longevity of single barrel trap guns that have fired tens of thousands of rounds of 1 1/4 ounce loads in their early history and more tens (maybe hundreds) of thousands of rounds of rather high pressure 1 1/8 ounce loads in the last seventy years, and are still tight. All this discussion is very interesting, but selecting a well designed, tight gun will prevent any of the negative effects of either pressure or recoil.

Mr eightbore and one last question for clarification if you don't mind.

What causes the gun to shoot loose? Is it pressure which is contained within the barrel, chamber and ejecta? Is it recoil which slams the barrels down, causing what we commonly refer to as barrel flip, that deflect the barrels which attempt to rotate around the hinge pin, place unequal torque on the hinge pin, puts severe stress on the locking mechanism(s) and batters the barrel lug against the frame which in turn transfers that force to the stock and finally to the shooter?

Mr Rocketman I asked this question earlier and you either missed it or are just blowing me off but I would really appreciate an answer.

Just how does the pressure, which is contained within a closed vessel (the chamber, barrel and ejecta), transfer energy to the metal parts of the gun causing wear, as you stated in your previous response, when there is no way to transfer tht pressure exerted from ignition of the powder charge to the frame, forend iron, hinge pin, and locking mechanism(s).

Obviously, the final cause is recoil, since high pressure loads of negligible recoil, like the .22 long rifle, will never cause a well designed and well fit double gun to shoot loose, or, at least, I don't think they will. The less than final cause is poor fit or design, or looseness before the testing period. A well designed and fit gun will never, in our lifetimes, shoot loose with any reasonable use of reasonably loaded ammunition. In fact, an exceptionally well designed and fit gun may never shoot loose when used with any quantity of any ammunition that will not blow the barrels. I don't know the details of the Boss gun that was used so extensively, but that would be an example.

Thank you.

TwiceBarrel, thank you for the thank you, but I don't see in my posts where I implied that pressure had anything to do with loosening a shotgun. My short answer is that recoil causes loosening, but only in a gun that is improperly designed and fit.

No you are correct that part of the post concerning pressure is directed to Rocketman.

Rocket likes to shakes things up with his amazing sleight-of-brain. Not to worry; next time this comes up, he'll be back to Newtonian orthodoxy. Pressure causes nothing when the results are case specific and dependent on wgt. of payload and "emphemerals" and velocity of payload. It sure is a fuse or initiator of the events under examination but as stated several times, receives no symbol and no quantification in Newtonian mechanics. I have yet to see the equations for Amosian mechanics. C'mon Don, you're the brainiac here, S or GOTP.

jack

Certain competition guns that I am familiar with seem to fall within the bounds of the guns which I described as indestructible regardless of the amount of use or the pressure or recoil of the loads used. Two guns with which I am familiar that fit that description are the Krieghoff clone of the Model 32 Remington, and the 680 series Beretta. These guns, set up tight and lubricated on a regular basis, seem to defy break in much less wear out. The two guns I have shot tens of thousands of competition and practice rounds with over the last twenty some years, a 22 year old 682 Beretta and a 42 year old Krieghoff Model 32, still drag on the hinges and have lever positions well to the right. The Beretta has had the locking pins replaced once, but the Krieghoff has had no work done at all. When the Beretta exhibited centered lever position after about 17 years of use, it was still very tight and dragging on the hinge, but I replaced the locking pins anyway to bring the lever back to the right. I have no reason to believe that any number of rounds could wear these guns out, regardless of pressure or recoil. My 87 year old Parker PHE Trap Gun probably digested as many or more rounds over the years, but I don't know that for a fact, so I won't use it for an example of longevity of a tight and lubricated gun.

Interesting. Mike, you really think that Uggies and Huglus are better built than Foxes? Time to sell your Fox, I guess, and buy one of each.

Let's quantify the difference in recoil from when your Fox was built to current day loads. If it was a 2 5/8" gun, max available load was 3 DE, 1 1/8 oz load--1250 fps. That's the same load as the current Winchester AA Super-Handicap. Recoil energy, in an 8 lb gun: 22.7 ft/lbs. If you happen to own a vintage gun (pre-WWII) with factory 2 3/4" chambers, the max available load was 3 3/4 DE, 1 1/4 oz--1330 fps. Recoil energy: 33 ft/lbs. Heaviest lead 12ga 2 3/4" load available today: 1 5/8 oz turkey load (don't have a DE for it)--1250 fps. That load's recoil energy, same 8# gun: 47.4 ft/lbs.

So . . . even going from the hottest short 12 to the hottest 2 3/4" 12 then available, you would have increased recoil by 50%. Go to the heaviest one available now, you more than double it! Which tells me . . . if recoil is the evil genius in this whole business, then why aren't older guns so mistreated--as well as new guns--shooting loose at an accelerated rate? That's a far greater increase in recoil than in service pressure, under SAAMI max standards.

And unless the Winchester geniuses were wrong, even well-made, well-fitted guns WILL shoot loose. Otherwise, why did they bother designing hinge pins of increasingly large size to replace the original, in the event of looseness? And note: That's on one of the more modern and stronger (as we know from the Winchester proof tests, in which all the other guns failed--the Ithaca and Fox under 100 rounds, while the 21 absorbed 2,000) of our classic doubles.

As for the example of the .22 insert . . . well, you now have a .22 barrel inside a shotgun barrel. What's the result? Heavier gun, heavier barrel. That's precisely what you do with a gun that's going to be exposed to higher pressures. Note the thickness of chamber walls on a .410, for that skinny little shell--which produces very little recoil. (The standard lead 3" .410 load, 11/16 oz at 1135 fps, produces a whopping 8.8 ft/lbs of recoil in an 8# gun. 410 barrels need to be that robust to absorb all that nasty recoil? But a .410, as we know, does produce increased pressure in comparison with the bigger bores.

In summary, whether you think pressure or recoil is the bogeyman, it seems to me extremely unwise to subject your gun to the forces of either, if they're in excess of those for which the gun was built. You may well get lucky and nothing will happen. Or you might get unlucky, end up with a cracked frame, gun off face, etc. And if you have never seen an off face American classic double--I don't care of what brand--I'd suggest you've lived a very sheltered life. The modern competition guns are a different story, because they're built for the shells being used in them. You would not expect them to shoot loose, or at least not until after many thousands of rounds.

I don't quite know what Larry said but he was very friendly about it.

I think in his round about way he is telling us that he was wrong and that recoil is the culprit for wear on an otherwise well maintained double gun.

One thing that has been left out of the discussion is the wear on the pin and hook caused by the physical act of opening and closing the gun. It has always been my understanding of the things that the pin was harder than the hook, and that wear on the hook was usually the cause of any looseness. Over a period of decades, shooting thousands of rounds, under sometimes less than ideal conditions with poor lubrication, wear on a gun will happen. If a gun is lubed correctly and shot with the ammo it was untended to shoot it will outlast the shooter. Pick up a 100-year old Parker with some wear: generally the action will wobble. But I'll wager the thing digested many many rounds of Super-X before wear became apperent, along with being opened and slammed shut with each round shot. And I'll also bet the reason "modern" guns do not seem to exhibit the same issues is they have simply not been around long enough. That and modern metallurgy. My $.02.

eeb that is a valid point. I have a L C Smith Quality 2 10 gauge made during the first half of the second year of production (1887) that is still tight on face with no play in the hinge. From it's condition you can tell it was well cared for but there is now way to determine how much it was shot but with 1 1/4 ounce loads which it was designed for and my moderate pressure reloads I think it easily could last another 122 years.

eeb;
If you go back & read my first post on this subject you will find I mentioned that most loose guns were the result of "Wear".
All;
There are several things which need to be borne in mind. Shooting a gun does not "Wear" it loose. "If" a gun is "Shot Loose" it is the result of metal deformation, not Wear.
2nd thing that needs to be borne in mind is that wall thickness has absolutely no bearing upon the forces tending to bend the hinge pin, deform the hook or stretch, bend or crack the frame. Thus in the example of the .22LR in an insert bbl the walls of the inseret containing the radial pressure is what takes care of the bbl, it could be shot from a Barrel made of River Cane. This has no bearing upon the back thrust of the cartridge. In this case one of the major differences is simply the size of the case, thus greatly lessened area for the .22's pressure to push against. 20K psi time .035 SgIn (approx area of the internal .22LR case) = 700 lbs thrust (No account taken of case wall grip). 11K psi times .44 SqIn (approx area of 12ga hull internals) = 4,840 lbs thrust (same conditions). But you "Rightly Say" we are talking of two different loads of differing pressures inside the same hull. It now becomes a lot more complicated. Note carefully though that a lead crusher will not read as high a pressure as a piezo/electric crystal. If the brevity of the pressure cannot compress a "Lead" piston to what it would theoretically be compressed by the pressure read by the PE crystal, it also isn't going to bend the standing breech made of a steel forging to the extent it should theroetically do from that same pressure. The peak of the pressure curve from say Blue Dot powder will be a lot flater than the peak of a Red Dot load for instance. Thus if a load is fired using each powder @ 9K psi for instance the 9K would remain longer with the BD load than the RD one. More metal "Bending, Stretching, Flexing etc would thus occur.
Bottom Line still is if you want to determine which load is most apt to burst yuor chamber, compare the peak pressures. If you want to figure which load will stress the hinge joint, frame, bolts & Stock compare the "Momentum" of the loads. If you compare the recoil using identical wt of gun for all loads the same percentages will be obtained. I did not point this out in my earlier post, but is necessary to keep all on the same level.
Another thing that should be remembered is a lot of these older guns are not as weak as many give them credit for. In my 1913 Lefever catalog the following are all the heaviest loads given for various powders in 12ga with "1¼ Oz Shot"
Black - 3½ drams (Guns over 7lbs)(My 8lb gun with 2 5/8" chambers should qualify here, as no chamber lengths are listed)
Bulk Smokless - 3½ drams by measure
Infalliable - 28 grains (3½ DE)
Walsrode -34grains (3½ DE)
Nobel's Sporting Ballistite - 28grains (3½ DE)
Note these aren't Pussy-Cat loads, & while true they do not exceed 1¼ oz they are well in excess of the above mentioned 3-1 1/8oz load stated as the "Heaviest" load guns of this era were "Designed" for.
No gun wt limitations were given except for black. Apparently Lefever Engineers were not aware of the fact the gun would recoil less with the Black because it burned slower than these other non-progressive smokeless powders.

Miller - You did mention wear early in this thread, now that I look back. The load you mention from Lefever, 3.5 drams and 1 1/4 oz of shot is an a$$-kicking pigeon load, even in an 8lb gun. You're right, the old guns were built to take it and still can, within reason.

Unfortunately, all black powder was not equal--any more than all smokeless is equal. So you go back to the black powder days and you add a bit of mystery to the recoil energy of those guns. That is, unless you know the muzzle velocity in addition to the shot charge.

I'd also note that in 1913, SAAMI did not yet exist. (It dates from the mid-1920's.) And prior to SAAMI, in this country, proof and service pressures were not yet regulated and standardized. Once they were, and once we'd switched to smokeless as a propellant, the hottest load available for the 2 5/8" 12ga was--and I have to make a correction here (print is SMALL in my old Shooter's Bible!)--a 3 1/4 DE, 1 1/8 oz load. 1255 fps, which I find listed at the same recoil energy I quoted before: 22.7 ft/lbs. So you're still jumping the recoil 50% just to get to the then-hottest 2 3/4" 12ga, 3 3/4 DE, 1 1/4 oz (1330 fps) at 33 ft/lbs. Not to mention the current hottest 12ga loads, which deliver over double the recoil of the hottest 2 5/8" smokeless loads.

I don't think anyone is saying recoil is a benign force. Obviously, however, since both SAAMI and CIP set pressure standards (and not recoil standards), neither is pressure. Best for the safety and integrity of our vintage guns to stick to loads for which they were designed--AFTER the establishment of an organization in which arms and ammo makers voluntarily cooperated to set standards. Better than talking about what Davey Crockett shot in Old Betsy.

At worst, recoil may bruise, or in the case of magnum rifle, detach the retinal laminae. Fragmentation grenades play hell with hands, eyes, brains. You can buy another gun but new fingers, eyes, forebrains aren't readily available. The proof houses and standards institutes are proving guns and setting operational limits for chamber pressure because they are concerned with preventing the latter. Someone here is speculating, implying, planting subliminal suggestions that proof houses and standard institutes want to safeguard your gun against wear. Stop that!

jack

Larry implies that the posters are claiming that there are no loose American guns. We don't claim that at all. What we are claiming is that a quality American double, set up tight and lubricated, will not loosen on the hinge in a lifetime of shooting with reasonable loads. Obviously heavily used L.C. Smiths and Foxes are rarely found loose when closed. Parker singles are seldom found in a loosened condition after tens of thousands of rounds. In the early period of their manufacture, 1 1/4 ounce loads were commonly used on the trap field.

The problem, eightbore, is the definition of "a reasonable load" for the gun in question. Seems everyone is missing the very critical chronology issue to which I earlier made reference: SAAMI was not established until 1926. Therefore, prior to that time, there were NO COMMON STANDARDS for the proof of guns in this country; no common standards for the proof of ammunition, nor the establishment of service pressure ceilings. I submit that, therefore, there was no definition of "a reasonable load" for all shotguns being marketed in this country prior to that time.

In other words, what was "reasonable" for a Parker, Lefever, Elsie, or Fox would not necessarily have been reasonable for a Long Range Wonder bought down at Acme Hardware. Unfortunately, lacking both a national proofhouse or a voluntary organization of arms and ammo makers (that would be SAAMI), Great Grandpa George Sixpack had no way of knowing what he ought to be shooting in his new gun.

The creation of SAAMI came about at a very critical moment in the history of shotguns and shotshells in this country. In 1926, the new Super-X was just hitting the market. That shell was longer (2 3/4" vs 2 5/8") than the old standard 12ga chamber, and hotter than the then-standard 12ga loads. So . . . we start with the fact that there weren't even any common proof and service pressure standards for the old 2 5/8" guns and ammo; add to that a longer, hotter load. (Ithaca had even switched to a newer, stronger design for its doubles--the NID--to deal with the newer, hotter loads.) It's at that point that the arms and ammo makers get together and say "OK, this proof level and service pressure are reasonable for 2 5/8" 12ga guns; these higher levels for 2 3/4" guns."

Think of this somewhat like OSHA--which, in spite of all its stupid excesses, manages to keep some idiots from harming themselves every year. Same deal with SAAMI--with a somewhat lower level of excesses. What SAAMI had printed on 2 3/4" ammo boxes was "Don't use these shells in guns with Damascus barrels, or in guns with chambers shorter than 2 3/4". Overkill? Yes, to a certain degree. But their view was, better to err on the side of caution. Sure, we know that some Damascus guns will handle smokeless powder loads (at proper pressures), and 2 1/2" guns will handle 2 3/4" hulls (at proper pressures). But the kicker is that the higher proof and service pressure levels for 2 3/4" FACTORY loads meant that they were not appropriate, either in most Damascus guns or guns with short chambers (which had different and lower proof and service pressure levels). And we also have to remember that back then, there were quite a few cheap, imported guns (many with Damascus barrels) that could not take the same loads as a Parker, Elsie, or Lefever--much less the new, hotter 2 3/4" loads. Or could not take them without wearing out in a hurry, or maybe worse.

That puts us where we are today. Thanks to those SAAMI standards, we know that we can take any new American-made 12ga with chambers 2 3/4" or longer, and we can shoot any American factory 2 3/4" load in that gun. We have that level of confidence because we have standards. And that level of confidence means that Joe Sixpack in 2009 is one whole heck of a lot less likely to get himself into trouble by selecting inappropriate ammo than was Great Grampa George Sixpack back in 1909.

But it stilla means that those of us shooting shotguns handed down to us from Great Grampa George--such as 12's built with 2 5/8" chambers, well before WWII--ought to be fed a steady diet of FACTORY 2 3/4" shells that exceed the velocity and shot charge levels established as standard for those guns by SAAMI. As for pressure, we don't know whether specific FACTORY 2 3/4" shells exceed the service pressure ceiling established for 2 5/8" guns--but we do know that the current SAAMI service pressure ceiling for the 2 3/4" 12ga is higher than it was for the 2 5/8" 12ga. So there's a very good chance that current factory shells are also overpressure in old, short-chambered guns.

Summary: You can say "My Parker (Fox, Ithaca, Elsie) whatever with short chambers has digested x thousand modern, 2 3/4" shells, and it's as tight as when it was new"--which is great, but which is relevant only to YOUR SPECIFIC GUN. It's what's called "anecdotal data". Because the next guy's gun might shoot loose--whether due to pressure or recoil we can continue to debate, but regardless--after having undergone the same use. If you want to PROVE that your gun is good to go with any 2 3/4" shell now made in this country, here's how you do it: submit it for proof at 19,000 psi. If it passes, continue to blaze away. But unless you do that, reasonable caution would seem to dictate that you ought to use shells loaded to no greater pressure, velocity and shot charge than were available on the market AFTER SAAMI came into existence. Those standards are known. For the 12ga, it's particularly easy to reload within those standards. Or you can buy shells loaded within those standards.

Unless someone has particular questions on this subject, that's where I stand.

Larry,

I have some questions, if you don't mind...

It should also quite well be noted the 2 3/4" shell was not introduced with the "SuperX" load. In fact drawings fron 1907 found in The L C Smith Plans & specifications book show the 2 3/4" shell as already being standard for their 12ga guns. Virtually all of my post 1900 Lefever's in 12ga also have 2 3/4" chambers. I of course cannot prove they came that way from the factory, but I also have no reason to believe that "Everyone" of them have been re-chambered. In fact the big "Theory" behind the introduction of the SuperX loads was the newly developed Progressive burning powders allowed higher velocities with a heavy shot load "Without" a resultant increase in pressure. Since, as correctly stated, we have no real record of pressure prior to the introduction of SAAMI, I think it totally & absolutely "Self Serving" to infer that all loads on the market prior to that time were "Low Pressure". In fact I do not believe there is a shred of proof the previous 7/8oz, 1200fps 20ga loads the Ithaca Flues had been digesting quite happily had a bit lower pressure than did the new 1oz, 1220fps SX loads which cracked frames. They did however have a heavier "Back-Thrust" to the head of the hull. I am old enough to remember when further powder developments allowed the introduction of the so called "Baby Magnums" in the 50s when standard length shells had their charges increased to 1 1/8 oz in 20ga, 1¼oz in 16ga & 1½oz in 12ga. As these shells were publically stated to develop no higher pressures than had their predecessors many assumed any gun they had been firing with the older SX's were quite suitable for these newer magnums, this was not always the case, but again not because of the higher pressures but the heavier back-thrust. Fortunately we have a readily available formula for comparing this "Back-Thrust, its called recoil. Given the same gun you can bet if a "New Load" kicks harder then not only "You", but also all the parts in the gun which resist the axial loads present from firing the gun are being put under a greater stress.

We've all heard the Super-X story in precis form and probably not a bad idea to hear more about the historical moment for the emergence of SAAMI. In the meantime, here's my old school testament about chamber pressure, recoil, and certainly "causal" relationships.

1) Pressure has no place in the calculation of recoil force. Knowing the wgt. of payload plus ephemera (wadding and powder charge), velocity of payload, and wgt of gun allows the predictive calculation of recoil of the gun.

2) Expanding gas CAN impart energy to the components of a pressure containment vessel (pressure relief valve, walls of the vessel). A shotgun at moment of firing is very much like a tank with a pressure relief valve. Expanding gas is held in containment by a piston or valve whose inertial or mechanical resistance to movement (or release) is also the condition for the creation of pressure. You could say that the vessel of containment "causes" pressure and not be much further from enlightenment than if you said pressure "causes" metal deformation and looseness in shotguns. Obviously, there is correlation of apparatus and chemical phoenomena which make possible events as disparate as: a) triggering a valve, b) overcoming the inertia of a plug or piston, c) rupturing the walls of a container, d) static maintenance of pressure in the container (in the case of hot gas, pressure in containment would decrease by dissipation of heat but would still be the classic extreme case of pressure which "causes" absolutely nothing cf. to the dramatic work done by shotguns and engines).

3) In past discussions, the mathheads and strict Newtonians have beat me about the head and shoulders until I have at least absorbed the idea that predicability of the resultant of chemical and physical events is vastly more important than which necessary pre-conditions may be termed in the vernacular "causational".

4) I still want to see the math in which peak (or durational) chamber pressure is incorporated in an equivalency of ratios to predict a single unknown (recoil force) one side of Mr. Equal Sign. Until then, I'll stick with the older vernacular that recoil of the gun as a whole and as parts (think freight cars slamming together on coupling) "causes" temporary frame deformation, barrel whip, radial and torque force around the axis of the hingepin, splaying of breech balls away from extension slots, battering of the stockhead, flexing of the stock wrist, general "Deacon's Shay" looseness, and ultimately the staggering flinch.

jack

"ultimately the staggering flinch."

This stuff is suppose to help Jack Not sure if it's to be applied prior to the 'staggers' or after?

Staggering forward of the line is embarassing, Doc! It appears to follow directly upon gun not firing or an inability to break a trigger or both but that's only mere temporal correlation and all of us here are aware that ain't what causes it. I prefer to take the cure with a "little Yuengle" from Pottsville PA or that Shiner Bock from somewhere in Tehas.

jack

Mike, there were no agreed-upon service pressure and proof standards for ANY shells or guns in this country prior to the creation of SAAMI. So . . . none, period, prior to 1926. That's not saying that gun and ammo makers didn't proof test their products; just that there were no common standards (contrary to all the other countries in the world with proofhouses).

Proof standards appear to have remained somewhat in flux, at least for a few years even after the establishment of SAAMI. LTC Calvin Goddard, I believe recognized as a ballistics expert back then, writing in "Army Ordnance" in 1934, stated that Hunter Arms proof tested 12ga 2 3/4" at 14,300. He adds that Parker followed "SAAMI standards": Proof pressure of 13,700 psi for 2 5/8" 12ga, service pressure of 9500 psi. 2 3/4" 12ga: Proof pressure 15,900 psi, service pressure 10,500 psi.

Good question about LUP vs psi, and when you go back to that era, you might well assume they're talking LUP--since that was what they actually measured then (although they called it psi). That would put the proof pressure of the 2 5/8" 12ga, following SAAMI standards, at around 15,000 psi; of the 2 3/4", around 17,000. Service pressure 10,500 psi and 11,500 psi respectively--which puts us at the current standard, with 2 3/4" shells. Additionally, Arthur Curtis--who worked at one time or another for a number of American firearms makers from the late 19th century until at least the 1930's--gave service pressure for the 2 3/4" 12ga at 9,000-10,000 psi, quite close on the upper end to current standards, assuming he was dealing in LUP.
Hope that helps.

Miller, I didn't say that the Super-X was the first 2 3/4" shell. I'm quite well aware that there were guns chambered at 2 3/4", and shells for them, before the Super-X appeared. However, it is generally accepted as the first MODERN 2 3/4" shell, using progressive burning powder. It was also a shell which increased pressure (by at least 500 psi, per Curtis) increased standard field payload to 1 1/4 oz, and increased velocity. Curtis refers to "high speed shot shells" introduced years prior to his 1938 American Rifleman article, and I'm pretty sure those are the ones he means. They certainly received a lot of glowing press, from people like Buckingham, and accelerated the changeover to 2 3/4" as the American 12ga standard. And it seems odd to me--since we certainly agree that increased payload + increased velocity = increased recoil, and since we also agree that increased recoil is not a benign force (at least on the stock, if not on the metal)--that SAAMI would stick to an antiquated service pressure ceiling rather than establishing a payload/velocity standard to protect our guns. Perhaps pressure still remains key, however much recoil has increased--and it certainly has, since WWII.

Rabbit, you're constructing a nice straw man there. I certainly never stated--and I don't believe ANYONE has stated--that increased pressure = increased recoil. In fact, if you go back the line a ways, I believe you'll find an example I gave of two loads that are identical in payload and velocity, one significantly higher pressure than the other--even though the higher pressure load uses a lighter powder charge. Powder burn rate has a whole lot to do with pressure . . . which is why, unless you reload, you can't be sure at all about pressure other than that it's within the maximum established either by SAAMI (US ammo) or CIP (European ammo).

Aha, I do believe someone or ones did provide the straw as I perceive a hint or two (perhaps from Rocket who disappeared down his silo)that non-catastrophic physical destruction of guns was somehow directly attributable to chamber pressure developed (without an intermediary called recoil) and someone sure as the devil was off on a sideways insinuation that SAAMI or IPC are on a mission to protect our guns from wear and tear by setting service pressure standards. Or maybe I'm blind?

Larry, with reference to your final two sentences, third graph, reply #547410 above, please tell me once and for all that SAAMI has or has not done something to "protect our guns" from non-catastrophic wear and tear. From the description earlier of the adoption of the 1.5oz load in 2.75" 12 ga., I would tend to believe that it has done nothing to that end; rather the dual service pressure scheme tied to chamber length was a consistent attempt to prevent catastrophic failure in two classifications of guns without obsolescing one classification by stating their inadequacy to meet the standards of another.

jack

Quote Lary Brown;


I do humbly appoligize for mis-interpreting what you were attempting to say. I now have absolutely no idea what you in fact did say. It is well to note that if the pressure was increased by 500psi as you quote Curtis as saying that represents about a 4.5% increase in pressure. On the other hand velocity of a 1¼oz load was increased by about 9% (1220 to 1330). Yet you want to say this 9% increase in force which the shell head puts upon the standing breech is totally of no significance, only the 4½% pressure increase. My personal advice to you is to stick to discussing models, grades, values etc etc of various shotguns of which you are extremely knowledgable. Leave the ballistics to someone else. I generally try to just ignore any ballistic statements you make, but I was in this discussion before you were so had little choice, as I do feel these matters need to be addressed.

Miller hit the nail on the head, as is usual, when he said "Larry, I now have absolutely no idea what you in fact did say." I must confess that I too am having trouble following Larry's posts. I think he is taking a cue from another longwinded poster who is constantly off topic and way too wordy.

My world will not end if we disagree, but I'm willing to answer questions and continue to discuss.

Guess I'm going to have to try shorter words or something. The fact that the Super-X was a "new" 2 3/4" load does not make it the first. The fact that the standard 12ga chamber length (prior to the introduction of the Super-X) was 2 5/8" does not mean there weren't guns out there with longer chambers. Just that they were in a minority. As to the rest . . . if you don't understand that there were no common standards for proof and service pressure prior to the creation of SAAMI, I don't know how to make that any clearer. Wow. . . my wife, who after many years just left a job in which her major role was to put engineer English into something "the masses" can understand, often expressed frustration. Now I can see why.

And thanks, Miller, but I can put words in my own posts. No need for you to do so. Increased payload/velocity/pressure of the then-new, hotter loads are ALL of significance in the guns in which they are used. I have a sub-6# Prussian Daly Featherweight. Even if I knew that the pressure on a 3 3/4 DE, 1 1/4 oz 12ga load were sub-9,500 psi, I would not shoot it in that gun. NOWHERE have I ever indicated that recoil is a benign force.

Rabbit, I agree with you: SAAMI has done nothing to compensate for the increased recoil generated by faster and heavier 12ga loads. Now my question to you is: Are you seeing a lot of modern 12ga guns shoot loose because of those loads? If the answer is no, then would that not indicate that there must be some other factor which is being regulated (like pressure, which SAAMI does regulate) that plays a truly critical role in metal wear? I'd add here something we have not addressed: The SAAMI pressure standard for 3" 12ga is the same as for 2 3/4" (11,500 psi service pressure), even though the shot charges are significantly heavier. Maybe someone ought to get their hands on a Ruger Gold Label and put a few thousand 3" shells through it. Volunteers?

Something else we have not mentioned in our discussion of classic American guns is that they are not equal. Even all Foxes, all Parkers, all Elsies etc are not equal. Example: Foxes had 4 different barrel weights, with a difference of 3/4 pound between the lightest and the heaviest 28" 12ga tubes. Parker made guns on several different size frames. Elsie made a Featherweight (not to mention the Long Range Wildfowl). Thus, whether an American classic double--properly cared for--could survive the increased pressure and recoil of modern American 2 3/4" loads might well depend on which Parker, Fox or Elsie you happen to own. A Fox with No. 1 barrels . . .totally different expectations than a Fox with No. 4 barrels. Although if you stuck with the hottest ammo available in 2 5/8" for that Fox, I'd say your chances are a whole lot better even with the lightest barrels.

How do I politely say this?

Bullshit

That is the only word that comes to mind.

[quote=TwiceBarrel Mr Rocketman I asked this question earlier and you either missed it or are just blowing me off but I would really appreciate an answer. I never intentionally "blow off" anyone. I'm sorry if my answers or the form of those answers caused you to feel "blown off."

What causes the gun to shoot loose? Metal to metal joint grinding and battering. Is it pressure which is contained within the barrel, chamber and ejecta? Yes, it is the forces on the joints needed to keep the joints closed while containing the firing pressure. Is it recoil which slams the barrels down, causing what we commonly refer to as barrel flip, that deflect the barrels which attempt to rotate around the hinge pin, place unequal torque on the hinge pin, puts severe stress on the locking mechanism(s) and batters the barrel lug against the frame which in turn transfers that force to the stock and finally to the shooter? No, you have intertwined the forces due to firing and those due to recoil. To understand the effects on wear and damage, you must keep these two sets of forces separate.


Just how does the pressure, which is contained within a closed vessel (the chamber, barrel and ejecta) (the vessel is not closed as the ejecta is free to move which requires conservation of momentum which generally assures recoil), transfer energy to the metal parts of the gun causing wear, as you stated in your previous response, when there is no way to transfer tht pressure exerted from ignition of the powder charge to the frame (pressure containment shows up as back-thrust force on the fences of the frame), forend iron, hinge pin (the hook and hinge pin absorb fore-aft force trying to separate the barrels from the fences), and locking mechanism(s) (the bolts and bites absorb the force trying to rotate the barrels upward from the action flats due to the center of back thrust force being above the hook/hinge pin center of force). [/quote]

You are doing great Rocketman, hang in there.
Too bad we don't have a stackup drawing to picturize all the roll centers, clearances, and the directions of the forces being applied.
It could be called, "Why a shotgun shoots loose", and be an FAQ stickey.

The timing of these controlled explosions (I know, oxymoron) moves through the shotgun like a wave. Each part accelerating like little dominoes. Heavy pieces being more difficult to accelerate, and taking a longer time of collision. Like catching a baseball. Human bucking up all the while, squashing the stock into the action.
Unfortunately, by the time the stock is accelerated, the chambers have been at,exceeded, and vented themselves due to the pressure.

So, I vote for excess pressure doing more damage first. Not to say, that as links in a chain, little weak parts along the collision highway could fail or be beaten to bits before the stockhead pulped. And be done below barrel burst pressure, or fatigue cycles entered the mix.

Sir I believe it is you that is intermingling the two separate forces.

Chamber Pressure acting upon the interior of the barrel, chamber and ejecta versus a totally separate force called recoil which has resulted from the ejecta being discharged from the barrel with an extreme amount of velocity (Newtons 3d law of motion. Remember recoil is totally independent of and not related to pressure. Recoil is only dependent upon the mass (weight) of the ejecta and the velocity of that ejecta as it departs the confines of the barrel. There is no transfer of the pressure forces outside of the chamber except for the expulsion of the ejecta. It is the force of recoil that causes the mechanical actions (back thrust, torquing of the frame, deflection of the barrels and transfer of force from the barrels through the frame to the stock that produce what we are referring to as wear.

OK, mark-up my respones as you see things.

Suppose we weld a solid plug in front of the chamber and the chamber walls and action are strong enough to contain the pressure. On firing, the chambers will experience radial pressure , which is not related to this discussion. The plug will experience forward pressure which will try to move the barrels toward the muzzle and is relevant to this discussion. The fences will experience rearward pressure (thrust) which is relevant to our discussion. Keeping in mind that force equals pressure times area, we can tell how much force is acting in each direction. The forward and backward forces are combined into axial force. Axial force till try to separate the barrels and the action. The hook and hinge pin will absorb most of the axial force and the locking bolts and bites will absorb the force trying to open the action in a rotational direction. The flexures between the hook/pin and bolts/bites will occur. Any grinding wear or battering wear will occur. The only thing that will not be present is recoil as there is no movement of ejecta, hence no recoil force.

Now, take off the barrels and fit a "sled." Have a shooter shoulder the gun's stocked action and have a helper strike the front of the sled with a maul. The gun and shooter will experience a force exactly like recoil without any pressure.

Why are modern guns not shot loose as often as older guns?
1. Better metal in the joints.
2. Better lube.
3. Less frequency of shooting after an extended storage period where the oil applied to the joint has run out.
4. Less firing to date.
5. Bigger, more robust joints.
6. Cleaner powders, wads, and hulls.
7. More rigirous cleaning and lubing.

How do I politely say this?

Bullshit

TB, you're contradicting yourself. Down the line, you talk about pressure acting within the chambers of a shotgun barrel. Of course British and other in the know gunsmiths would tell you that you need to look for a thin spot ANYWHERE along the barrel . . . although they're more dangerous the closer you get to the breech (more pressure . . . even holes in the barrel out at the muzzles--aka ports--won't hurt anything). So, why do you suppose Fox bothered with 4 different weights of barrels--if not to help the heavier guns better withstand the pressure AND the recoil (remember, gun weight offsets recoil) from higher pressure, faster, heavier loads? Why were the Super Fox and the Elsie Long Range Wildfowl made a whole lot heavier--if, again, not to mitigate the effects of pressure and recoil?

But hey, if you want to go ahead and shoot the same shells in a 6 pound double as in an 8 pound double and expect the former to suffer no more harm than the latter . . . blaze away!

Fox separated their barrels into 4 groups by gauge and weight simply so the assemblers would choose barrels of similar weight when striking and joining the barrels.

The Super Fox was a whole different frame size than the standard 12 gauge made heavier to better accomodate the Becker over bored barrels (11 gauge) and manage the increased (you got it half right) recoil generated by the Western 2 3/4 inch Super X and later 3 inch ammunition.

What Miller, Twice Barrel, and I agree on and Larry and Rocketman apparently don't is that a tightly set up American gun of quality can take this pressure and recoil business and forget about it, just about forever, as long as the locking mechanism is kept clean and oiled. There is no way that all of our Parkers, Smiths, and Foxes that are still tight and on face were somehow kept from exposure to heavy loads and volume shooting for eighty to a hundred years. No, they survived heavy loads and volume shooting and will continue to survive. This pressure and recoil is a non issue for owners of good quality, well maintained guns.

Rocketman your contrived examples are so far outside of the normal function and sequence of how a shotgun functions that they really have no bearing on this discussion of what is the genesis of accelerated wear in a shotgun that it has no relevance. Additionally in your rambling responses it appears that you have totally disregarded Newton's laws of motion in all of your reasoning.

A high quality shotgun is designed and built to not flex or expand with any reasonable load. No flex, no expansion, no wear. That's why well maintained shotguns 130-140 years old are tight as new.

Let's leave those barrels on and assume there is 5-6 thou gap between the barrel hook and hinge pin to begin with. The barrels will be the sled. Repeat those strikes to the muzzles a number of times and the gap will grow...the gun will loosen due to "a force exactly like recoil without any pressure."

I understood the question to be, "Why?" I did not understand we were somehow taking sides on wear of American made guns, nor did I vote on that issue. Sorry if I misunderstood the topic. I take a look at my American guns and say what I see later.

I keep scrolling thru Rocket's complete "embedded" page. Haven't seen that before; a new level of html manipulation there. Afraid I'm beginning to see the light on this pressure as bad actor short of catastrophic destruction thing (of course I did bump my head on the fridge so could be that). Thanks for staying on the pot and labouring mightily, Don! I've assumed all along that the release of pressure is nearly instantaneous owing to the forward movement of the shot charge but perhaps a lot of mechanical devilry can occur in the very short duration of peak pressure.

Now, Bill, if high-quality [break action] shotguns are designed NOT TO flex under reasonable loads, why do so many, antique and contemporary, have the radiused root at angle between water table and standing breech. Is this attempt to avoid a stress riser a precaution against the anticipated effects of unreasonable loads only or those of all loads, reasonable and unreasonable?

jack

We have to get to the basic principles of how physis works. The examples may sound contrived, but they show the underlying physics of the situation.

They all flex. Wear can be mitiated by robust joints, low pressure, hard steel, good cleaning, and high pressure lube. But, they all will wear if used. Could a gun be worn off-face by simle cycling without firing? Wash all joints dry of lube, toss in a little grit, cycle a few hundred times, and measure. Non-firing cycling has a large movement under very low pressure. Firing has very small movement under high pressure. They will both wear the gun.

No, zero, zip, nada, mechanical joint is completely immune to wear. Good design and maintenance can make the wear small, but never eliminate it.

TB, you needed to keep reading in McIntosh's book: " . . . selected according to how little hand-work would be required FOR A FINISHED GUN OF PREDETERMINED WEIGHT." Mr. Smith wants a 12ga for upland hunting. If I look in my 1940 Shooter's Bible, I find that--assuming Smith wants a gun at the lighter end of the scale--he can get one, 26-28" barrels, right around 7 pounds. That "predetermined weight", based on Smith's order through his local dealer, is almost certainly going to end up with 4 weight barrels, to get him what he wants. If he later decides he wants a heavy waterfowler (without going to the Super Fox), 32" barrels weighing right around 8 pounds, he can get that too--but it'd be with #1 or maybe #2 barrels, to match that predetermined weight. And since we agree that the barrels are key to dealing with pressure, and since we also agree that a heavier gun will handle increased recoil better than a light gun . . . you buy your gun for the purpose in mind, and you use the loads that make the most sense for that gun and that purpose. You might well shoot those new Super-X loads in your waterfowler; you might not in your upland gun, especially if it came from the factory with 2 5/8" chambers. Especially if we're talking prior to WWII, there were still WAY more factory 12ga shells offered in 2 5/8" than 2 3/4".

As far as well-maintained shotguns being as tight as new after 100 years or more of use . . . Unless the same person has owned the gun for 100 years, or passed down detailed records of said gun's use, we don't have a clue why it's still tight as new. Might be it was never shot all that much. And if it's loose, although we can sometimes detect signs of abuse, we don't really know that either. How do we know that the gun isn't loose because of the loads shot in it? Seems to me the recoil party is in retreat there, because if it's recoil that causes wear, then more recoil than the gun was built to handle is going to shoot it loose. In fact, I think 3 or 4 people have already suggested that.

The problem with most vintage guns is this: what we know about them is anecdotal (only applies to that particular gun) and almost always incomplete. It's like the 10 year old car with 10,000 miles on the odometer, only driven back and forth to school by the little old lady teacher. Who maybe has a mechanic boyfriend who tampered with the odometer. But comparing a car to a vintage (pre-WWII or older) gun, with the car, you might well buy it from someone you know, who bought it new. FAR less likely with a vintage gun.

Didn't the English design the weight of their shotguns based on the weight of the intended pay load ?

So the various writers and researchers of Fox shotguns have wasted a lot of time.

I'm not a Fox man could you explain...

Fox barrels typically have a number on them.
1- Heaviest
2
3
4- Lightest
Unless it was struck off in finishing.

Particularly helpful in online searches as the barrel number can give you a general idea if a gun is going to be heavy or a lightweight.

Now Mr. Brown lets talk a minute about the all time best seller of the Fox line, The Sterlingworth model. I hope that you will agree that they were made with all four barrel weights. How many of those do you suppose were ordered to a set of specific specification? We could ask Resercher but I think that we would find that they were primarily ordered as a "stock" gun for sale at retail Sporting Goods stores and Hardware stores of the day and that relatively few were ordered to a set of specifications.
Now compare the number of Sterlingworths to the number of graded guns and I think that you will find that following my logic most Foxes were not ordered with a specific barrel weight and if you consider the variance in wood even if a gun was ordered to a specific weight the density of the wood will have more influence the the variance in barrel weight. By the way my Sterlingworth with #2 wieght 32 inch barrels weights 8 1/2 lbs on he nose. So is the differnece in weight between your 8 pound gun due to the weight of the barrels before striking or is it due to the density of the wood.

They may not have been ORDERED with a specific barrel/gun weight but they were most assuredly MADE to a specific weight.

Mike that is quite possible but I have never seen such a listing of minimum and maximum specifications.

Yes, I totally agree if we pluged the bore & made the chamber strong enough not to burst but the breech was sealed by the cartridge & it did not rupture then it would be correct to say that the pressure & area it acted upon would be the total consideration, recoil would not enter as it was correctly stated there would be none. This however is not the manner in which our shotguns function. This would in efect be dealing with a static pressure load, but in firing we don't have a constant static pressure. "IF" the full pressure a normal powder charge is capable of generating was applied to the gun there is likely not a gun in existance which could stand the strain, either the chambers or the breech, it would just be a matter of which let go first. However as soon as the charge starts down the bbl pressure begins to fall away & we generate the "Curve". To go back to basics as you say R'Man I think you would find if you placed a hydraulic piston hooked to the hinge pin with its ram pushing against the standing breech, centered on the firing pin hole & having same bore as the internals of the case & pumped up the pressure equal to that developed by firing a standard shell with proper gauges hooked up to measure deflection of breech, hinge pin or any other critical part, you would find the deflection greater than firing the shell which produced identical "Peak" pressure. Now this will be because the peak falls away before its full effect can act upon the breech. Now I am not sure I can word this in a technically correct manner, but I am throughly convinced that;
#1 recoil is of course brought about by the presure acting inside the gun. As noted it requires movement in opposite directions of different parts to occur.
#2 the same force which is creating this recoil is also acting upon the parts of the gun under axial load.
#3 I am in total agrement that under your scenario of plugging the bbl while recoil would be stopped the thrust against the gun would not only not be stopped, but rather increased.
#4 I am still convinced that as long as the gun is operating as intended with the charge rushing down the bore the amount of strain put upon the parts of the gun for all the above mentioned reasons will be more in proportion to the recoil than the "Peak Pressure".
#5 I am totally convinced that a 1oz 1200 fps load @ 10k psi will not load the gun as much as a 1¼oz 1330fps load @ 9k psi.
#6 "IF" someone has the resources & equipment & knowledge to set up a test & can show that the higher pressure load will indeed load the gun more than the lower pressure load producing heavier ballistics I will offer my most humble appologies. Until then we will just have to agree to disagree.

Larry; I think if you do a little more research you will find that indeed several American Co's had "STANDARDSIZED" the 2 3/4" 12ga shell in their guns well prior to the "SuperX" load. All 12 ga guns prior to the SX with 2 3/4" chambers were "NOT" custom guns nor was the shells "Special Order".


PS; I might well add that under the conditions of the plugged bbl scenario the 1oz load with the fast powder which under ordinary conditions produced the higher pressure would in this case produce the lower. Reason; under this condition the heavier load will contain a considerably heavier charge of a slower burning powder & will have suffcient time to fully burn & deliver its total potential. Of course it should be understood that even under normal conditions it is doing more work, thus a higher total "Average Pressure" just a lower peak. I do believe R'Man you are delving just a little too deep in total theory & ignoring a few actual occurances.

PPS; I have to the best of my knowledge & Ability been talking about the "WHYS" for this entire thread.

2-p has my unwavering respect as a well learnd, experienced and resourceful person. He and I have not, over the years agreed completely on all subjects. However, we are always willing to discuss and learn.

Rabbit, to answer your post, I think that most guns of quality are designed to flex as little as possible with any load likely to be used in it. Yes, some flex is inevitable, but so little as to be negligible in causing wear. Yup, Rocketman, we don't know how many times these tight old bird guns have been fired, but we do know how many times, within a few tens of thousands, some of these old single trap guns have been fired. Virtually all of them made by Parker and those by Ithaca above serial number 400,000 are still tight with little or no maintenence. The flex factor must be very small in those guns.

You need to look harder, TB. I find them in my 1940 Shooter's Bible. In fact, I find them right under the description of the "Sterlingworth Grade". Weight ranges for each of the 3 gauges, depending on barrel length. And for the most part, what's going to determine the weight of the gun you end up with is the weight of the barrels--given the fact Fox used those 4 different weights.

Miller, you seem to be specializing in straw men of late. Where did I ever suggest that all 2 3/4" 12's built prior to the advent of the Super-X were custom guns, and the shells special order? I'm going to try one more time, so in the future you can use MY words rather than YOUR interpretation of them. The Super-X is generally regarded as the FIRST MODERN 2 3/4" load. It developed higher pressure, and its combination of payload and velocity also produced recoil greater than that produced by MOST 12ga loads then on the market (and certainly more than any of the 2 5/8" 12ga loads). Shortly after its introduction, American gunmakers began to switch to the 2 3/4" chambered 12ga as "standard". That being said, even quite some time AFTER the Super-X appeared (1940, referring again to my Shooter's Bible), there were still far more factory 2 5/8" loads on the market than 2 3/4". Remington, for example, offered only one 2 3/4" 12ga load in its Nitro Express line, while there were 5 different 2 5/8" loads to choose from in its Kleanbore line. (You had your choice of either chilled or soft shot!) Pretty much the same deal with the company that started it all: Two 2 3/4" Super-X loads, one with standard lead, the other with the copper-coated Lubaloy shot. Meanwhile, 5 different 2 5/8" loads in the Xpert line. Same story with Peters: one 2 3/4" load; 5 different 2 5/8" loads in the Victor line.

So even though I believe every American shotgun manufacturer had stopped making 2 5/8" chambered 12's several years previously, you could not state that 2 3/4" SHOTSHELLS were "standard", by any means, even as late as 1940.

I'd add here, re the condition of vintage doubles: one reason some of them rattle is quite likely the fact that the chambers have been punched out to 2 3/4", and since that happened--at one time pretty much common practice with American gunsmiths (I have Ralph Walker's article on the subject, courtesy of Brownell, dated 1974)--those guns have digested a diet of shells they were not designed to handle. Higher pressure, heavier shot charges, increased velocity--often a combination of all of the above. And, as John Brindle points out in his DGJ article, how can removing metal from a chamber--right where pressure is the greatest--render a gun more suitable for hotter, heavier loads? Unfortunately, it is not at all unusual to find vintage American doubles, not factory marked as 2 3/4" but with chambers measuring that length. Chances are excellent such a gun came from the factory with a 2 5/8" chamber.

Perhaps the 1940 shooters bible did publish an average or target weight most probably based on input from Savage's marketing peopel and we all know how accurate/honest they can be now don't we. But Mr. Brown you are dead wrong in your statement that the barrel weight stamped on the barrels will determine the final finished weight it is an indicator but nothing more.

My NID 4E #457465, from 1927, I seem to remember, is a heavy trap model, 8# 11oz. It has likely been shot somewhere between 100,000 and 250,000 rounds of trap loads. Probably never shot with heavy water fowl loads. Outside condition indicates very good maintenance. It is just about time for it to be put back on-face. They will shoot a long time under proper conditions, but not forever, even under optimal use. Open and close one without firing enough times and it will have to be put back on-face. My Parker "D" #2 frame, #107406, 7# 15 oz with 28" cut damascus bbls, has a seriously beat-on exterior, but shows little signs of being shot. It is tight on-face.

You suppose those folks at Savage (and Fox before them) spent any time trying to balance those guns before they sold them, TB? I do. If they didn't do that, they would have been putting out some guns with some very unusual (read undesireable) handling characteristics--like the balance point out close to the forend, if you have really long, heavy barrels matched up to a really light piece of stock wood. Somehow, I don't think that would've been real good for their reputation.

Here's a little experiment for you to conduct: Get yourself a good scale (like electronic postal) and a handful of doubles, preferably as they came from the factory. I just did that (although 2 of mine have pads), and here's what I found: the greatest difference between the weight of the barrels and forend, together, and the stock and receiver was . . . 4 ounces. In one case, less than an ounce difference between the two. Now if you consider that Fox had 12 ounces difference to work with, at any given barrel length between heaviest and lightest, I'd say barrel weight is a whole lot more than an "indicator" of final weight--because if Mr. Smith wants his 28" Sterlingworth to weigh as close to 7# as possible, it's a dead certainty Fox/Savage would not slap heavy #1 (4/2) or #2 (3/14) barrels on that gun; highly unlikely even #3, at 3/10. And yes, I know wood density will always cause variations of 2 or 3 ounces one way or the other . . . but don't you suppose those guys could find a stock and forend that would match up nicely with Smith's desires--and yes, one could order a Sterlingworth just like one could order a graded Fox--and, together with those barrels weighing 3/4, give him something awfully close to 7#? And would you think, even in a gun that's not special ordered, even shipped to Acme Hardware, those guys at Fox would take a set of 4# 28" barrels, slap on a forend . . . and then mate it up with a 3 1/2# stock/receiver? Sterlingworths (and Trojans, and Ithaca and Elsie Fields) may have been the "knockabout" guns made by those companies, but they did not do stupid stuff like turn out guns with godawful balance. So you give me the overall weight of a Fox as it came from the factory, tell me if it's splinter or beavertail and whether it has ejectors or not, and if you give me the length of the barrels, I'll tell you what # they are. Could possibly be off one number, either high or low (maybe someone cleaned out pits, opened chokes, etc), but I think it's that good of an "indicator".

I finally went to the Upland Journal thread that inspired this one. Larry Brown's argument there jogged loose all the schlerotic buildup of Newtonian commonplace, accepted expression, received wisdom, and cant which tends to clog up little brains like mine. Maybe the argument about the history of SAAMI pressure standards is cohesive and easier to follow there where less standpatter ire and less point by point special pleading are in evidence.

I took for granted that service pressure ceilings are adopted to protect gun and shooter from catastrophic failure and nothing more. Time to look once again at the product of better minds than my own. Many thanks also to Rocket and Pipes, who, if I'm not mistaken, can swallow the words "imparts energy" (backthrust) without wretching.

I'm currently stuck on how one would establish a formula for proportionality between chamber pressure and threshold and rate of battering damage? Is onset of perceivable cumulative damage to the closing and locking components of a break action gun only related to an either/or of recommended acceptable pressure vs. over-pressure? What role does the "rule of 96" play in damping interface battering as well as "unitized" recoil? Should it have changed at some historical point to a Rule of 96 and then some? Arguments here about weight of target guns indicate that it has. Is "high-pressure" lube really more of a necessity in the mechanical interfaces of these old guns than some of us (me) have thought?

jack

Of course, I'm still thinking about this business of when a quantified pressure from one source in one situation is not the same pressure from another source in another situation, as per 2-pipes below:



Lot to take in here!!

jack

Good to see ya rumminatin', rabbit. A rumminatin' rabbit --- worth ponerin' on its own merit. Do note that I disagree with 2-p on the above, believing that the force transmission through the steel takes place in very small amounts of time; way, way fast enough to keep up with the chamber pressure changes.

R'Man; now just think about this one a minute, in this scenario you would obtain closed cell pressures. Certainly this would give higher pressure than an ordinary firing of the load.


I can see no place for the recoil to start other than from the energy imparted to the standing breech from the back thrust of the shell head. The friction of the charge being pushed down the bore would in fact impart a forward motion to the bbls, but a lesser force than is being imparted to the breech. Many years ago in my National Guard days I fird a 3.5 Rocket Launcher & there was in fact a distinct forward pull as the rocket went down the tube, which of course was totally open to the rear. This same condition should exist in the shotgun bbl, but of course is un-feelable due to the offsetting effect upon the gun's breech. Thus when the charge is fired there are actually opposing forces trying to seperate the breech from the bbls.

Now I do believe we are mostly in agreement, with the exception of the part time plays in the mix. In looking at the peak pressure in available pressure curve drawings with the faster powders this peak is a virtual point, but with slower powders more of a rounded hump. Now I think we all know this peak of pressure will not compress a lead piston to the same extent it would be by a static load of the same pressure, thus LUP is lower than PE pressures from an identical load. Now the only real difference I can see here is the steel of the action is being placed under tension rather than compression.
If a 1200 fps load was given absolute uniform accelration & allowing for 29" of travel to clear the bbl then total bbl time would be .004 sec. Since acceleration occurs quicker near the breech actual time is more on the order of .003 sec. Now the top of that pressure peak is just a "Dot" on that 29" curve.
Yes I believe time does play a very important role in this situation. If it did not I do believe you would find a very large pile of destroyed guns, but you don't. If you calculate aformulas for strength of steels vs wall thicknesses, hinge pin shear, frame deflections etc, etc you will find many running on the Ragged edge, or over, yet they just keep on keeping on with loads far heavier than they were designed for.
While just a machinist & not an engineer I have studied everything I could come up with on this & similar subjects for about the last 40 years. I have come up with no other satisfactory explanation.

I also remember firing a 90mm Recoiless a couple times and having the impression that the tube wanted to go down range. Plastic in the bores of my new old Merkel 200e indicate that the friction of the wad is REALLY trying to drag these barrels downrange.

jack

Just so your loader wasn't standing behind that 90MM when you fired it, Jack. I fired one of the old 3.5's; they gave us a nice demonstration beforehand on what the back blast would do to one of the wooden cases the rockets came in.

Rocketman or 2-piper, Would either of you please answer rabbit's question about the high pressure lube for older guns. My gunsmith had treated special lubes with scorn,reading this thread has me questioning a man I never doubted.
And, are there any words to live by coming out of this discourse. At what point will loads damage our vintage guns or at least hasten their wear? Thanks,Justin

justin, I use Mobil #28 grease on hinge pin/hook, bolts/bites, lump sides, exposed lever work, and FA attach mechanism. Apply sparingly, clean, and refresh after each shooting session. "Clean" is likely as important as characteristics of the lube. I'd shoot with recent application of 3 in 1 Oil without qualms, but not after extended storage and no refresh. Oil is fine for short times, but wax and grease are better for long term. Modern, high pressure lubes are cheap and available, so why not use them. If I were Mr. Gunmaker Smith, I'd probably use Vasoline to limit my personal skin exposure to trace elements that might be in more exotic lubes, but I don't worry about that with occasional, shooter type handling.

I keep my loads to less than 7500 psi and usually shoot 7/8 oz (12 bore). There is no "point" of sudden sear increase - think a curve (it takes something pretty severe to blow-up a gun unless it has a seriously weak spot) only the more you strain 'em the faster they wear. Also, being on the --- ahemmmm, well, OK, call what it is, cheap side, I like to save powder, lead and gun wear by shooting light, low pressure loads. I do not see, speaking of me, load performance issues near as much as I see shooter issues.

Larry I have no interest or intent in participating in your silly little "experiment" because it has absolutely no bearing one way or another on the facts that that I have presented. Dave Noreen or Mr. John Callahan are the two preeminent experts on Foxes that I know. If they fail to corroborate my statements I will change my opinion but remember there are two statements that need to be commented on ("The numbers assigned to barrels prior to striking was done to assist the joiner in selecting barrels of like weight to facilitate finishing) and "the weight number assigned to the raw barrels before striking is an indicator of final weight but nothing more in fact is was common that when lighter weight barrels were not available heavier barrels were heavily struck to obtain the desired weight". Additionally contrary to McIntosh's statement that "weight stamps are nearly always clear and crisp on heavy guns, decidedly faint and blurred on lighter guns" is opposite of my own observations as my heavy weight barrel gun which is most likely a 2 is almost totally obliterated and the barrel weight codes on my four of my 3 weight barreled guns are very clear and distinct The barrels on my two 16 gauges that have the weight code obliterated most likely started life as 3 weight barrels a full 6 1/2 and 5 1/2 ounces heavier than their final finished weight if Fox would have been attempting to make these barrels to a specific weight they could have easily select 4 weight barrels and saved a whole lot of filing and polishing so as with Lefever guns with Fox guns the exception is often the rule and one should really avoid making broad sweeping proclamations.

I'd say, more likely, you don't want to verify what I've found because you're afraid it will upset your preconceived notions.

Straight from McIntosh, on Fox barrel-making: "But just as frames take time to file and finish, so do barrels, and the hand-work needed to strike a set of heavy tubes into a pair of lightweight barrels could eat up a sizeable chunk of company profit." Right . . . they just hammered away, costing the company more worker time, which = money. Why not just start with the correct weight tubes in the first place?

Last sentence in that chapter: "According to factory standards, barrels could not vary more than one ounce per pair from the weight specified." Thus, assuming barrels that haven't been cut or reamed significantly, if you put them on a scale, they ought to come out very close to the weights listed on pp 152-154. I have weighed a few sets of Fox barrels (certainly not dozens), and have found those tables to be quite accurate. And given the variation available in barrel weights, the best indicator of the overall weight of the gun will be . . . the weight of the barrels.

Justin, that's probably the key question! We can debate all day about whether it's pressure or recoil we need to worry about, but it seems to me that the BEST solution--which should leave you on safe ground on both counts--is to stick to loads no heavier than those available when your gun was made, and within the then-established service pressure standards. For example, if you own a 12ga originally chambered 2 5/8", 1 1/8 was the heaviest shot charge available. Velocities in the 1200-1250 range, depending on whether you chose the 3 1/4 or 3 DE load. The beauty of reloading for vintage guns is that you can come up with a bunch of formulas that will get you there, easily under 9,500 psi. And if you're talking target loads, you can go a whole lot lighter on shot and much lower on pressure.

Rocketman, I've been using plain baby oil,wiped clean after shooting. I don't know how this compares to the #28 grease but I'm sure ii's much thinner. I was warned about grit staying in the lube being the worst offense, so the thinner the better. I don't know what to think,but I will look at the grease.
I also keep my psi in that 7500 range but opt for the 1oz. loads. It's when I have the chance to go pheasent hunting that I wish for the bigger shot charge. Still keeping the psi at around 7500 I look for the 1&1/8 oz loads. Those damn western birds seem awfully tough to bring down,even with #4s. So will a couple of boxes of do much damage? That seems a pretty tricky question.
Being cheap in this game is a virtue to me. Unfortunately I've become hooked on IMR 7625 which is one of the more expensive powders out there. It was Bell's articles on the virtues of 7625 having the same pressure curves as black powder that attracted me and now I can't quite it. Is there a viable alternative that is just as soft. I haven't found one yet.
Thanks for answering,Justin

L.Brown, Thanks for the advice. As you see from my post above I keep the pressure low. It's the shot charge that's vexing. My guns were all built pre 1898 and are proofed for the 1oz loads poular at that time. I don't think I can nail a No Dakota pheasent to the ground with 1 oz of shot. So I shoot the 1&1/8 load and it seems to work. At least it keeps me from thinking about it when I pull the trigger. Justin

As you no doubt know, Larry, sonic shock was worse for the loader [of recoilless rifle] than for the gunner because the loader faced the tube which put his ears in line with the shot and the backblast. When I was the loader, it seemed to be about the closest thing to "hot noise" I'd ever heard.

I've gone from a mixture of 3-in-1 and Vaseline [RIG lookalike] to Mobil 1 20w50 as a hingepin, hook, rulejoint knuckle and lockbolt lube. May try that Mobil grease. I also like IMR7625 for loading 16 ga., Justin.

jack

It's easy to blame cracked stocks and loose actions on recoil or pressure.....it could just as easily be blamed on improper care.

I'm undecided if I like Ken Owens hinge pin lube or a light film of Sperm Whale Oil better.

justin, use the grease and wipe it clean after shooting or exposure to grit. Grease does not "attract" grit, but will, as will oil, hold it.

A box here and there of thoughtful heavier loads is not the issue. The steady diet is. Like a car engine, we usually don't run it at full power for very long. Full power is there and has its uses when needed, but not as a steady diet. Heavy target guns are, like some stationary engines, made for full time high output.

Hey Larry what do you want the workforce to do when they don't have the proper materials to do the job as efficiently as planned? Are they supposed to sit around on their butts waiting for the next batch of proper weight barrels to show up? Come on Larry think

Miller is saving me a lot of reading time, mostly because he is brief and to the point, and, more important, he agrees with me. Regardless of all this pressure and recoil stuff and a wordy dissertation on the workings of the Fox and Savage gun companies, Miller says it all in part of a sentence. "they just keep going on and on". In fifty plus years of high volume shooting and high volume gun buying, I have yet to have a problem with wear or damage caused by firing in a well maintained shotgun. End of story. Oh, not really the end. I use oil, not grease, and I have never bought a container of gun oil, use the stuff that comes in quarts at about $2.49 for enough to last several years, maybe decades. It's never failed me.

TB, you're trying to make something fairly simple into rocket science. You yourself have suggested that Sterlingworths weren't custom ordered guns. Well, some of them were . . . but most certainly were not. Therefore, the guys putting them together had a simple solution available which did not involve spending a lot of time hammering barrels: If you have heavy barrels, match them to a stock with denser, heavier wood. Voila: heavier gun . . . but one that still BALANCES quite well. Reverse also true: match lightweight barrels to lighter stock wood. That is, unless you think maybe a whole lot of Foxes have really p*ss poor balance. (I don't.) Somebody special orders a light gun, I suppose it's possible they'd do some work on heavy tubes if that's all they had. Or they could wait (not likely that long, given the fact that, with the exception of one year, even during the Depression of the 30's they were making at least 2,000 12ga Sterlingworths/year) for lighter tubes.

The above is why I suggested you conduct the same experiment I have (weighing barrels and forend, comparing to stock and receiver), because it would clearly establish in your brain that you don't just mix those elements willy-nilly. Unless maybe you want, as a result, a gun with the handling characteristics of a 2 x 4. I don't believe that would've done good things for the guns' reputation.

Justin, I have a couple 1930's vintage Brit guns, Army & Navy (made by Scott), 2 1/2". Most of the time, I just shoot the Kent Gamebore Pure Gold 1 1/16 oz loads. But here's a reload, straight out of the Alliant book, that I've used in my tight barrel (or when the birds are flushing farther out in general) with excellent results:

Fed Gold Medal hull, Fed primer, Fed 12S3 wad. 22.5 grains Unique. That'll push 1 1/8 oz shot at 1200 fps, pressure 7300 psi. Or, if you can live with a bit less velocity (1145 fps), use the same hull and wad, Rem primer, 20.5 grains Green Dot. 6800 psi.

What is it that they say about teaching a pig to sing? I give up. You are hopelessly full of misinformation.

What's with all the "hammering"? You guys don't like filing? do re me fa so la te oink? I had the impression from somewhere that barrel blanks were forged, needing only final bore, chambering, exterior fairing and fitting. Are you referring to the mysterious activity of "hard fitting"? Those little tippy taps wouldn't reduce wgt.

jack

shoot ammo the gun was designed for and you cannot go wrong. ed

What are you calling "custom ordered" ?....a certain barrel length.

I'm not a Fox man but from what I've saw of them I suspect only their higher grades were "custom ordered"....and even then I doubt if many were ever fitted to the buyer.

L.,thanks for the recipes. Since you mentioned Scott,and my Monte Carlo has the Scott cross bolt I wonder what the efficacy of the third biteor cross bolt has on the wear of the gun?
This is also a ploy to get you guys to stop scratching at each other about Foxes. Justin

You should've asked if blOw-torch case coloring effected the integrity of the steel in shotgun actions ?

Ya know jOe I've always wondered about the effect the case coloring process has on old actions,and I never heard of someone doing it with a blow-torch. Doesn't sound good.

Jack, here's McIntosh's quote. I should've used "striking" rather than hammering: " . . . the hand-work needed to strike a set of heavy tubes into a pair of lightweight barrels could eat up a sizeable chunk of company profit."

TB, I'm not sure about KS, but up here in Iowa, we eat our pigs. We don't worry about teaching them to sing. If you didn't spend so much time giving vocal lessons to swine, you might develop a greater understanding of some fairly basic and simple concepts concerning shotguns. Like when the factory is turning out 40 or more 12ga Sterlingworths per week, it's not likely that all the barrels they're working with are all heavy or all light. From McIntosh, again:

"In a shop where guns are made largely by hand, the forgings may all be the same size, regardless of what size and weight the finished piece might be, but for production guns there is an obvious advantage in having components machined to several sizes. The nearer the components are to finished size, the less hand-work required." We talk about all the "hand-work" involved in building the American classic doubles, and there certainly was a good bit of that. But they were basically machine-made, hand-FINISHED guns. They came out of real, honest to goodness factories . . . unlike, say, most British doubles.

Joe, you could get barrels from 26-32" on any gauge Sterlingworth. And although each barrel length had "standard" chokes, you could custom order any choke you wanted, no additional charge. Certainly the vast majority of Sterlingworths were bought "off the rack", but from any of the makers of classic American doubles, you could custom order just about anything you wanted: specify a weight, nonstandard stock dimensions, etc.

Justin, I remember text and illustrations from a couple of sources (think maybe Vol. 1 of The Modern Shotgun and in one of Garwood's books) indicating that all locking bites located top of breech (not only Greener and Kersten but also rotaries and even non-locking doll's heads) have the advantage over underbites of being further from the hingepin, allowing them to act thru a longer lever arm against rotation about said pin. Whether they are battered to a state of distension and deformity faster than are underlugs and sliding lockbolts I have no idea. The longer lever arm applies to both the translation of the opening movement around the hingepin to the lockbolt as well as its restraint by that bolt; would there be potential for a larger battering movement but a milder force applied than would be the case for bottom bolting?

It has been suggested that accurate fitting of crossbolt and underbite[s] to share the load applied on firing is difficult of accomplishment. I tend to believe that an inexpensive gun with multiple locking (Noble Arms m410) might well have a Greener which is more for show and not much for go. I can see no justification for redundancy of underbites unless they share the mechanical load equally. Perhaps Purdys are fitted with rigorous patience and each pair of bolt and lug takes a share of the load right out of the box. Again, using the example of a Spanish gun made to a low price, I would assume that one bolt waits its turn on the other which is a closer fit initially. I think they would tend to work in concert (dividing the load) after the tighter fitting of the two is "battered" to a tolerance of movement equivalent to that of the other as fitted.

My recently acquired Merkel from the late sixties has only the Kersten X-bolt. Even the Germans are able to sacrifice painstaking to a price point. Notice they stuck with the top bolting rather than the double underlugs. I don't know if that would have been a decision based entirely on economy of manufacture or if the company reputation for quality and longevity was served well enuf by the Kersten alone.

I've always wondered about the efficiency of floorplate-piercing lugs (recoil lugs). Do they share the work? How much and for how long?

jack

That word "striking" is a denotative morass. We've listened to the barrelwgt. arguments about the Fox and heard that the weight stamps are frequently what? Struck off while "striking"(draw-filing). Tents and camps are struck and they're no longer seen. Coins are struck and images and numbers appear. Striking is also a loose synomym for hammering. Very convenient.

jack

As a catch up note, I have not been ignoring this thread, but not had much computer time the last few days & all of yesterday kept getting "page cannot be found" when trying to log in. Will offer a few thoughts on recent issues & will try to give the rest of my thoughts on the original question later when time permits.
1st; There is one great difference between black & Smokeless propellents, Including 7625. Black powder burns at a very similar rate regardless of confinement, smokeless does not. In the scheme of burning rates black is a fairly slow shotgun propellent, but rather rapid for rifle use. The burning speed of black is due primarily to its make-up with further refinement from its grain size. It is made from very fine "Priming Powder, 4FG up through coarse grain cannon & blasting powders. 2FG & 3FG are the granulations most used for shotguns. Due to its characteristics you could drop 2 drams of 2FG in a primed 12ga shotgun hull, wad it & drop 3/4oz shot & if you shoot it immediately you can just push a thin card on top to keep the shot from rolling out & don't even bother to crimp it. Stick this shell in a gun & fire it & you will get good balistics at a very low pressure. Try to duplicate that with a slow smokeless, including 7625, & you will most likely end up with the shot charge trapped part way up the bore between the wadding. Burn rate of smokeless powders are controlled partially by shape & size of the granulation, but primarily by retardent coatings. The slower the powder, the more retardent & the higher the pressure required to keep it burning effeciently. Fast powders are meant to be used with normal velocities & lighter shot charges, slow powders are meant to be used for higher velocites & heavier shot charges. They should be used for their intended purposes, nuff said for the "Wise".
2nd; "If" I were commisioned to fit up a shotgun having double underbolts & a cross bolt, time & expense not a factor, here's how I would do it. First of course the breech end of the bbls would be fit to come tight against the standing breech with just a wee bit of clearence between their flats & the frame table (bout the thickness of a piece of writing paper). The front surface of the rear bbl lug would be cut on the arc of a circle centered on the hinge & fitted very closely to cross members in the frame bar to assist the hinge pin in carrying the axial load. The lower portion of the front lug below the notch would be shaped as a cam to allow the bolt to come forward on opening the gun bringing top lever back to center & pushing the bolt back in closing, doing away with the need for one of those tedious little ol lever latches to hold it open. The front bolt would be cut straight & given just enough clearence to run freely, no real need for it to actually do any bolting, just the purposes above stated. Rotational bolting would be accomadated by the notch in the rear lug. This could either be cut straight with just bare minimum clearence to allow it to close or cut as a wear compensating wedge. For the former the top lever would always stop centered, while for the later it would start right & rotate around as wear occured. The cross bolt would then be fit to absolutely insure it had a tight bearing on its "Rear" surface to prevent flexing of the breech away from the bbls. If properly fit it would of course also have some bearing on its lower surface to assist the rear bolt it countering rotational movement but this would for the most part be superflous. Utlizing the long bolt of the double underlug system also allows the rear bolt to pierce the bolt having bearing in front of, beside of & behind the lug. As the bolt is pulled up in load this gives it a more equal bearing over its length than if the load is just applied to its End. There are of course many other systems which have been used, many with great success, but this is my take on the very popular double underbolt with top crossbolt system.