doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 2 3/4 shells in 2 5/8 chambers

I'm sure that this has probably been covered here before, but I could not find anything through the search, so humor me.

I've recently come into possession of an old Fox Sterlingworth with short (2 5/8") chambers according to the measuring tool at the shop I bought it at. It seems to have some of the heavier weight Fox barrels, since it was a good 1-2 pounds heavier, and had noticeably thicker barrels at the muzzle than the other beat up sterly next to it on the rack. From what I've researched, a lot of these older guns were purposely built with slightly shorter chambers, since the attitude at the time was a slightly longer shell would create a better gas seal.

Anyways, I have not been able to find any information concerning shooting modern 2 3/4" shells in these shorter chambers. By "modern" I mean using modern 2 3/4" plastic hulls with my standard low pressure load I use for the rest of my doubles. I just wanted to see if anyone shoots 2 3/4" shells out of 2 5/8" chambers, and if you could weigh in. If it was generally considered "safe" it would make my reloading a lot quicker, since I have thousands of 2 3/4" hulls and if I could shoot them safely, it would sure beat cutting down a few hundred hulls.

I know that firing 2&3/4" in a 2&1/2" chambered gun has been tested to only increase pressure by roughly 10% and that's 1/4" so I would think 1/8" would be even less of a problem especially in the gun you've described

Hi, this should be of some help, about 2 1/2" chambers, but close enough:

http://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=35050&page=1

Interesting read.

Good Luck!

Greg

You're mixing up two different issues. If your Fox is from the Philadelphia era, it was made with 2 5/8" chambers because that was a common chamber length for American 12ga guns at the time, and all kinds of 2 5/8" shells were available. If it's from the later Savage era and is marked 2 3/4" but has 2 5/8" chambers, then it's because Savage intentionally short-chambered the gun to get better patterns from the old paper case shells.

However, there is no advantage in shooting longer PLASTIC hulls in shorter chambers. Modern plastic wads take care of the shot protection/pattern improvement issue. So what you're doing if you're shooting modern American 2 3/4" shells in a 2 5/8" gun from the Philly era is that you're using shells that may generate higher pressure than the service loads for which the gun was designed. (Service pressures increased about 1,000 psi from the old 2 5/8" shells to the new 2 3/4" shells.) And on top of the pressure increase from the shell itself, you've got another pressure increase from the longer shell in a shorter chamber. Combined, that might be as much as 2,000 psi. The gun will probably handle it OK, because as you noted it's pretty stout. But in the long run, you may not be doing it any favors.

Reloading modern 2 3/4" hulls for old guns with short chambers is a different story. Because you control the pressure when you reload, you can work up loads which are well below the maximum service pressure for which an old 2 5/8" gun was built, which was about 10,500 psi. Not hard at all to produce even 1 1/8 oz hunting loads that only run about 7,000 psi. So even if there's a pressure increase of 1,000 psi from the longer hull in the shorter chamber, you still have a comfortable margin for error.

Long answer, but it's not exactly a straightforward issue, especially when you throw in the practice of intentionally short-chambering guns back in the paper case era.

Note this is what the originator of this thread said he desired to shoot.
It is also noted that until fairly recent times, well into the plastic era, that SAAMI specs allowed for a minimum chamber length for the ""2 3/4"" shell of 2.614". 2 5/8" = 2.625" or .011" longer than the minimum specified.
One also wonders what changes Fox made when the new heavier loaded shells came out in the 1920's to their guns. They no doubt would have anticipated their use with these heavier loads.
Anyone have any knowledge as to what modifications were made by Fox, or any other makers, When WCC introduced their new shells which would become known as the SuperX??

Thanks for all the information everyone. I neglected to mention that the gun is a Philadelphia Fox from 1918, so I'm assuming that the shorter chambers were the standard length at the time.

If you're loading low pressure shells don't worry, you won't hurt anything. Paul

AND, if you measure the common plastic emptys, you will find they are about 2 5/8 not 2 3/4. About the only 23/4 that I find are the Federal Papers. However with low pressure loads it will be a negligable increase in pressure. Even shooting 2 3/4 Fed Papers in my short chambered guns , I can not tell any difference

Woops . . . I missed the low pressure part. Sure, if you're already loading low pressure, you're good to go.

I don't know whether Ithaca's switch from the Flues to the NID came as a direct result of the Super X, but the timing is about right. After Savage acquired Fox, they supposedly lengthened the chambers on all guns returned to the factory for work to 2 3/4" as a matter of course. Guess that shows they thought their short-chambered guns were good to go with the new, longer, higher pressure loads.

I load lower pressure loads, about 8500 psi, in 2 3/4 inch hulls for my 2 5/8 inch chambered 20 gauge Sterly completed in 1926. Even if there is a 1000 psi increase in pressure I'm below the loads that the gun was designed to shoot. I do try to keep the shot weight to 7/8 ounce and the velocity to 1200 fps to keep the recoil reasonable in consideration of the old girl's wood. But then again, she's just a spring chicken compared to my Joseph Lang which was completed in 1866.