doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 2 1/2" chambers and 1" cones

I think the main thing here is that factories have so long warned us against using longer shells in short chambered guns. This was however based predomintely on the "Load" on the inside of that longer shell, not the length of the case itself.
A similar thing existed with shooting "Ball". Most Muzzle loaders were cylinder bore & it was common to mold balls to about .010" under bore size. As choke obring came in fashion shortly after breech loaders came into general use it was not considerd desirable to stuff a .719" ball into a shell & fire it through a .690" choke, so choke bore guns began to be marked "Not For Ball". Of course as long as that ball was smaller than the choke no problem existed (other than accuracy) so that mark was dropped over 100 years ago. Even today I hear people say it will "Ruin" a full choke bbl to fire a Foster Slug through it even though they are purposely built to go through the tightest choke they are apt to encounter. Many "Facts" were based on a certain set of circumstances, but once ingrained its a long battle to get folks to accept they are not applicable to "Different" circumstances.

On the Brass shells, I have only a very meager collection of them but all the old ones I have (also newer ones) in 12ga measure just under 2½" thus should be suitable in virtually any 12ga except a 2" chambered one. I have no idea why Parker added the caveat about their use with smokeless powder. One of my "Thin Brass" shells is plainly marked on the head UMC Co/No 12/Smokless. My very first experience in reloading was done using all brass shells with DuPont Bulk Shotgun Smokeless. Info for so doing was taken from a Lyman loading manual from the late '50's.

In 10ga I have all brass shells measuring "Just Shy" of 2½", 2 5/8" & 2 7/8". I assume that 12ga brass shells were made in longer lengths than the 2½", I just don't happen to have any.
Due to the extra internal capacity a heavy 1¼ oz or even a magnum load can be put up in these 2½" brass case, but that doesn't mean of course they should be fired from a light 2½" chamber gun proofed for the standard load for its length.
All of the brass shells I have are for standard chambers, I don't have any of the ones for the smaller chambers.

Joe, why you try to distort my words? Where did I personally say never shoot shells longer than the chambers? What kind of play is that? And I SHOULD provide data and actual research showing the results me champion...?
Go to h*ll Joe.

I personally used factory loaded 2 3/4" cartriges in some of my vintage guns with 2 1/2" chambers. But some of these guns such as Collath 16G double can't be used with 2 3/4" cartriges and I told why.
All data and actual research is in your hands allready. Longer shells develop higher pressure in short chambers. HIGHER, not lower or equal, but higher! This is the only data you have to remember.
All the rest are for experts and for people who knows a lot about guns.
Personally I won't take risk and tell Patriot 'Go ahead! Buy light loaded 2 3/4" ammo in WallMart and shoot it!" I didn't see his gun.

Doug, my reference was to 2 3/4" SHELLS, not HULLS. Your question was, why not shoot 3" 12ga SHELLS in 2 3/4" chambers. My answer was that since 2 3/4" SHELLS are readily available and inexpensive, the question should rather be . . . why do it in the first place? And factory 2 1/2" SHELLS are more expensive than even very good 2 3/4" target loads. But then you know that, or should.

Gough Thomas repeated the same experiment as Burrard, and came up with the same results: Factory 2 3/4" shells, loaded to appropriate pressure limits for the gun in question, produced no higher pressures when fired in a gun with 2 1/2" chambers than did 2 1/2" shells. (I believe he used factory Eleys.) It's what's IN the shell--see both Burrard's and Thomas' reference to American factory 2 3/4" loads, which have a higher service pressure than their Brit equivalents--that causes the problem, not the extra length of the hull.

And by the way, if you actually measure the fired length of some of those 67.5MM hulls which are OK for 2 1/2" guns, and compare them to some American factory 2 3/4" hulls, you will find that they are almost the same length. In some case, exactly the same length. And in a few cases, the 67.5's are longer. When this discussion arose a few years back (when I thought we'd finally driven a stake through its heart), I assembled quite a collection of hulls, put them side by side, and found those very interesting results. So, if those 67.5MM shells are all OK in all 2 1/2" guns (all properly inspected, Geno), then why would a 2 3/4" hull generating the same pressure (or less), which is in fact no longer (or maybe even shorter), be a bad thing?

I no longer have that nice collection of empty hulls. However, I recall quite clearly that I did not find A SINGLE ONE that actually measured 2 3/4" in length. They were all somewhat shorter. If you have a chamber that's 2 5/8" rather than 2 1/2", chances are quite good that most 2 3/4" hulls will not enter the forcing cone, and the rest will enter it only a very short distance.

I should add here that, as in all things, there are some exceptions. There are some 2 1/2" guns--usually pre-20th century, and with very short and abruptly tapered forcing cones, where even the 67.5MM shells (to which Geno just gave his blessing for all short-chambered guns) won't work. You can end up with blown ends, etc, and you have to use shells that really do measure 2 1/2" when fired, or less. But these cases are pretty rare. And the solution is pretty simple. If you fire a 67.5MM shell or a reloaded 2 3/4" shell in one of those guns and if you blow the end off it, stop. Don't do it any more. Stick with the real shorties.

And Doug, since you seem to be big on facts, not theory . . . do what I did. Assemble yourself a collection of fired factory ammo, in 2 1/2", 67.5MM, and 2 3/4" lengths. Then come back and tell us how 67.5MM shells--which can, in fact, measure as longer or longer than 2 3.4" hulls--are always good to go in 2 1/2" chambers. (And, by the way, I did not find ANY 67.5MM hulls that were as short as 2 1/2". Which means, by your previous statements, that these are NOT the proper ammunition, because they are longer than the chamber in question--assuming it's really 2 1/2".) I guess those 67.5MM shells must be good not because they're the right length, but because they're measured in MM. And since that comes from Europe, and the guns come from Europe . . . suppose that's one way to look at it.

Larry:

I personally shoot 2.5" hulls which I buy or trim to size when new, 12,16 and 20......the 67.5 mm are available primarily in other parts of the world as are 65 mm, I don't buy European ammo for the doubles......I also don't run around measuring hulls either, because I know what works......what I do observe is the condition of any hulls in a particular gun after firing........

If the European proof houses stipulate that 67.5 is o.k. in 65 mm chambers, then you must speak to them with your hull measuring scenario, I am sure they would love to hear from you......

Being the 'technical' type you appear to be Larry, I am sure you are aware of the fact that most German & Belgium 2.5" doubles have sharp cones and will clip and damage the end, (or separate in two pieces) if 2.75 shells are fired in those guns, or maybe you only shoot other guns or are not familiar with that scenario, or maybe you grind out all your short cones....?....

Why is there so much resistance against shooting the 'correct' ammunition in any gun.....?.......Because some writer in the UK said it's o.k., is that the reason....?........Is it because you are cheap-frugal (you mentioned cost) and don't want to buy 2.5", or load 2.5"....?....Are 2.5" cases too much trouble, even though they are available most everywhere.....?......

As mentioned earlier, I have found that the 2.5" hulls pattern, shoot and last longer when fired in the "vintage" un-butchered 2.75" chambered guns as well.........probably because those chambers were machined and coned to fit the ammunition of the day, which was primarily 2 5/8 and 2 1/2 paper.......common sense one would think............

Since you like to measure---measure an old as fired 2 3/4" paper 'rolled' hull pre 1925, ..........then measure a modern star crimped 2 3/4 hull and compare overall length........

Since the SAME LOAD fits in both size cases-hulls for our vintage guns, what advantage is there to using a 2.75" in a 2.5" gun....Please explain what advantage there is.......availability, which we've already covered.......tell me, what is it.....?.....Don't reload....?.....Too lazy to put a short kit on the reloading press.....?.....Maybe just personal preference......?...........I would guess that is the reason.........?.....None of the other justifications make any sense whatsoever.............?.......Never have, never will......Have any of you people ever shot and patterned 2.5" hand loads.....for comparison....probably not.....?....

No two double guns, even from the same manufacturer will shoot the same pattern or have the same pressure peaks.......this is why the proof houses will not condone shooting 2 3/4 shells in 2 1/2 inch guns..........the other reason is that some bozo will eventually buy some high power 2 3/4 shells off the shelf and stuff them in there....with obvious consequences.................

I like what Salopian said in September of '06 when the same subject was extensively discussed......"play with fire and you will get burned"...."Did your momma advise you to stay back from the river before you fall in"............Or HoJo's from the same '06 thread: "I believe in using the shells that fit the gun"....and many, many more...........

I think everyone should shoot what they want........

Larry;
As I believe in giving credit where credit is due, I just have to jump in here. This is undoubtably the best post I have ever seen you make.
I hope though you won't mind if I add onr little caveat. Anyone who loads & shoots old guns, Learn to look first & see just what chamber & cone is there "BEFRORE" firing that first shot. I am in total agreement that if the end is blown off "STOP", but it would have been better to have realized the chamber was short & had that abrunt step & to have never fired a longer shell in it in the first place.
I don't have any 67.5 shells to check but did quick check on a couple of compression formed 12ga 2 3/4" fired hulls, one Rem one Win & they measured about 1/32" short (2.72} or 69mm. I measured the length of a single factory loaded 2 3/4" shell having an 8-fold crimp & it went 2.325" (59mm). Note that even if the chamber (with normal cone length) did in fact measure an exact 2½' this would have an end clearence of .175" or about 4.5mm. This would be ample clearence to not impede the opening of the crimp as noted in my previous post. "This" particular shell however "SHOILD NOT" be fired in guns chambered for the nominal 2½"/2 5/8" shells Because it is a 3¼de-1oz load put up with only SAAMI specs thus not guaranteed to be low pressure.
To quote Larry here, "Its The Load" that rules this one out, not the length.

Uh Oh Joe Wood, now you've gone and done it. You called Geno out and now he has told you to "go to Hell".

You're gonna look like such a dolt once Geno provides you (us) with, how did he say, ahh yes... "There were tonns of papers used up for these themes over here and all stuff was very detailed reseach." You're screwed now Joe, that is once he post all this information. Of course, for him to provide this service he will probably have to charge you for it.

Dustin

Geno, I apologize if my post upset you. It was genuinely intended to keep this discussion "fun" and to encourage both sides to contribute any data or information they're aware of. Perhaps American humor just doesn't translate very well into Russian. Or maybe the Russian culture doesn't understand the "wink" we Americans often use. Anyhow, how about avoiding personalizing your frustration or anger.

Let's clarify the specific point we're debating: suppose I have a gun chambered for 2 1/2" shells and fire a shell of that length that generates 6,500 psi. I then fire a 2 3/4" shell in the same gun that generates exactly the same 6,500 psi peak pressure. What significant difference is there? We would really like to know.

Have a great day!

Perhaps I, as a certified English-Russian interpreter, might as well step into this cross-cultural discussion. Geno's point is that while one gun will generate "exactly the same 6,500 psi peak pressure", another gun, of different barrell dimensions, will generate 7,500, or 8,500 or more. He has (and I have) seen 2 1\2" chambered guns function nicely with 2 3/4 loads, and other that showed evident signs of overly high pressure, like tearing off the head of the shell when fired (Geno, remember the topic about Oleg7's Hollis a couple of years back? there were pics of the shell, and the barel dimensions that showed exactly why it happened. Just one example.). I take it for a fact that if your gun shows high pressure signs, you'd better stop, no matter what a DGJ article or some net worm like me says on the suject. And it's good to know in advance which you have, before you get the action loose or worse. Thank you for your attention .

Oh my goodness, surely anyone who experiences signs such as you describe would immediately stop shooting the shells and determine the cause! Personally, I've never seen any such symptoms in my guns and I shoot 2 3/4" hulls in a couple dozen with short chambers. In fact, most of my hulls get reloaded a number of times, sometimes as many as a dozen.