doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Pressure vs recoil in old guns

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.