doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 2 3/4" in a 2 1/2" Chamber

This question has been debated ad nauseum on this and other Forums. What is often cited as Gospal is Sherman Bell's writings in the DGJ. As a Degreed Engineer with Graduate study and research in Metalurgy, I have found Bell's articles to be superficial in content and approach as well as potentially dangerous for others to use his results to justify thier use of shells for which a shotgun was not chambered. When an item is manufactured, it is engineered for a specific set of requirements. To change those requirements is folly when dealing with shotgun chambers. I will not debate this again but simply note that there is at least one person with academic credentials that does not agree with Bell. EOT-Dick

I didn't mention proof or any other technical issues in my post. I was referring to CHOICES that folks make.

It is about pressure, pressure & pressure.

Dick it is spelled 'gospel'.

All I can suggest is the you read Sherman Bells articles and anything else you can get your hands on. The naysayers will always yell loudest. Gather information and make a decision for yourself.

'May' was my word to condense thousands of words on dozens of pages in his articles.

Why not use 3" shells in a 2 3/4" gun. Because there is not a single 3" shell ever produced that is LOW PRESSURE. Many fine British, Spanish and other guns have 2 3/4" chambers but are still designed for LOW PRESSURE.

Dude, bizmuth(sic) was designed for older guns that can not handle STEEL shot.

Last comment for the moment on this thread.

This has been studied forever. I have an American Rifleman article from the 1930's concerning shotshell pressures and chamber length (among other items) as they were setting up SAAMI.

No one has mentioned cost. 2 1/2" shells are not common on the shelves of American gunshops. Having them delivered to your home is prohibitively expensive for many of us. Particularly when we have already stretched the budget to its breaking point to buy a fine older gun.

In fact loading LOW PRESSURE shotshells is one of the few areas of reloading whre you can still save signifigant money.

Of course you can (and I have) trim hulls to 2 1/2" but this adds time, cost and complexity which can quickly make the process not worth the effort.

I recently got my first English sxs, a hundred year old 2 1/2". Spent the first 60 years of my life KNOWING you can't shoot 3" in a 2 3/4" gun, etc. I researched the topic for a couple months. Gogh Thomas and Sherman Bell both say, with proper pressure loads, you may be o.k. That said, I'm reloading and buying 2 1/2" for my gun. First reason, it is fun to have something new and totally different, second reason it seems prudent to me.

That said, there is a portion of this topic I've never seen addressed. Does anyone know, if you do shoot 2 3/4" in a 2 1/2" gun, does it affect patterning? Any additional pressure would be generated by forcing the payload into a more restricted area. My flawed logic tells me that would deform shot, and possibly cause the pellets to "bounce" through the forcing cone.

Steve

OK, How low a pressure would be considered low enough? The load I have in mind to use will produce no more than 6700 PSI. Not to mention that I doubt that I will shoot more than 250 rounds per year in this gun.

I try to stay below about 8000 psi service pressure. This is slightly below what the gun was originally proofed for as a service pressure.
The former owner of my gun, shot boxes and boxes of modern field loads that were most likely loaded to about 11,000 psi with no ill effect.
If upon firing your handloads, you find that the ends of your cases are getting torn and shredded, then I would say that you might want to stick with 2 1/2" cases.
Just to save on cases! Thin walled hulls like the old style AAs are probably least likely to give you trouble.
I am speaking from ten years of my own experience with nitro proofed guns in good condition. I have read all the books and have made my choice with the particular guns that I use.
It really is up to you to decide.

FYI to Steve and anyone else loading for 16X65s or 16X67s,

ALL the recent 16 gauge Remington (black hulls) and Fiocchi marked hulls I have are actually 67 mm, even though marked 70 mm. These hulls I use unaltered for reloads to be used in 65 and 67 mm chambers. All my old doubles are Husqvarnas (actual 65 mm chambers) or German-made (actual 67 mm chambers), nearly all with the unaltered, nice tight chambers and bores common to such guns. 24 gram (7/8 oz) and 28 gram loads at 1100-1200 fps in 67 mm hulls perform really well in these guns -- as they should, those are the loads these guns were designed for. Ditto for some lightweight Husqvarna and German 12X65-chambered hammer doubles.

Elsewhere on this Board are data giving chamber pressures for the Remington and Fiocchi 16 gauge shotshells. I know that the factory Remington shotshells with 28 grams shot and actual 67 mm hulls have chamber pressures well above 10.000 psi, but, think I recall that the chamber pressures of the Fiocchi 28 gram loads are well below that.

Niklas

Mike,

But Dick has technical degrees for godsake . . . from a University no less!

Dick,

For the record there are several other people with technical degrees on this board who do agree with Bell's work - within the carefully delineated limits of his testing. Please note the many caveats that are used by him throughout his articles.

Until more extensive empirical experiments are conducted on damascus barrels by you or anyone else, I'll stick with Bell (and the host of others, including the proof houses, that agree with him.)

I'm out on this thread. I don't mean to be rude in my response, but admit to responding to what I perceived as "I have an engineering degree and Bell doesn't, therefore, I am the only one capable of understanding this."

Ken