doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Would You Buy an Out of Proof British Shotgun?

Dig makes an interesting obsvervation


The US made guns go through a manufacturer's proof, but once sold there is no longer a requirement for the gun to be checked for proof. Some of us have the barrels checked out to ensure the gun is safe, but nothing more. We put additional value on an English gun in proof. In the same way, some of us won't pay as much for a US gun with chambers opened and other barrel changes to the gun.

Ken

I would never buy any gun whose chambers had been lengthened unless I could check the wall thickness right at the juncture of the chamber and forcing cone. This is a tricky spot to measure on a double. Was the reamer cocked so as to take more metal from one side? I would want to measure where I could and eye ball the chambers. This is coming from a guy whose left little finger was blown off by a burst barrel. This WR may be perfectly safe but proceed with caution. People who lengthen chambers can have no grasp of barrel stresses and turn a reamer into a deadly weapon. Yeah, it makes a lot of sense to remove metal from the most critical area of the barrel so as to shoot heavier loads. That's the ticket.
nial

"The US made guns go through a manufacturer's proof"
I was not aware of a Federal requirement to proof firearms.

The issue has been discussed as far back as 1895
http://www.la84foundation.org/SportsLibrary/SportingLife/1895/VOL_25_NO_04/SL2504014.pdf

July 27 1895
Call for Government Proof House for Nitro Powder Testing
http://www.la84foundation.org/SportsLibrary/SportingLife/1895/VOL_25_NO_18/SL2518019.pdf

U.S. makers voluntarily test their own guns, no doubt with personal injury lawyers in mind



As I recall we had a long and contentious thread regarding this issue about a year ago.

Yes Drew, I remember the thread well since I was the devil who started it. In this connection, I don't think we have or ever had a problem here in America with newly manufactured guns. I believe the gun companies always have, and still do proof/manufacture their guns to a high level, a level where their guns will safely handle the highest pressure and the most stout loads. Where we do have a problem, however, is in these guns, like the English Westley Richards gun in question here, where there has been some sort of a barrel alteration, such as lengthening the chamber or others like honing bores, poor reaming out of forcing cones, where a gun may or may not be safe and is just sort of passed off to either a knowledgeable gun person or a more ignorant unsuspecting consumer who has no idea what constitutes a safe gun or even what 'in proof' means. I, for one am fond of the British system in terms of the proofing of guns, which takes the guess work out for the unsuspecting.

Here's the real problem with American guns: Back when the changeover was made from short chambers to 2 3/4" as the more or less standard for 12-16-20ga guns, it was not really a problem. Looking at my 1940 Shooter's Bible, I find WAY more factory shells available in the short lengths (2 5/8" for 12ga, 2 9/16" for 16ga, 2 1/2" for 20ga) than I do 2 3/4" shells. But after WWII, by which time American gunmakers were no longer producing short-chambered guns, those shells began to disappear. The common solution when you consulted your local gunsmith: just go ahead and lengthen the chambers.

The problem with that simple solution was that most gunmakers proofed the short-chambered guns to a lower pressure standard than those with 2 3/4" chambers. The difference wasn't huge--around 1,000 psi or so. However, by the time you figure that you're going to get some additional pressure (although again, not a lot) by firing a slightly longer shell in a shorter chamber, you may now be pushing 2,000 psi or so over the service pressure for which the old American short chambered guns were designed. Because most American guns were somewhat overbuilt (at least in comparison to British game guns), this usually was not a problem as far as "catastrophic failures" go. But it may well result in a shortened lifespan for the gun in question, in terms of shooting loose, if fed a regular diet of factory 2 3/4" shells.

That's why, as suggested, it's very wise to check the barrels on any American gun on which the chambers have been altered. (A good guideline: if it wasn't originally stamped 2 3/4", it probably started life with short chambers). And to stick with either low pressure factory loads (like from RST or Brit/Euro ammo makers) or low pressure reloads in guns that have, or originally had, short chambers.

My personal belief is that the 2 3/4" chamber "Marking" did not generally appear on US made guns until after the introduction of the newer progressive burning powder shells as the SuperX/Express etc. t can be generally assumed any US made gun carrying a 2 3/4" mark was designed, built & proofed with these shells in mind. Prior to this, which began in the early 1920's many, many US guns were built with 2 3/4" chambers but unmarked as to length. It can also be safely assumed these guns were not proofed for the heavier load. It is definitely not a guarantee that all unmarked chambers on early US guns started shorter that 2 3/4".
It is also duly noted that all US made guns carrying a 2 3/4 mark do not in fact have chambers which measure a full 2 3/4" long. In fact until only fairly recent times SAAMI specs for a 12 auge 2 3/4" chambered gun listed minimum dimensions as slightly under 2 5/8" & a minimum cone of 4/10"/.400 (5� per side). Such guns were designed, built & proofed for "ALL" 2 3/4" shells available at the time.

Thanks for your imput Diggory.

Oddly, within ten minutes of posting yesterday I was offered a Stensby of Manchester hammer gun. One barrel in proof and the other 1 thou. out. It would have required too much other cosmetic work to make it viable. A plain back action sort.

The way round it, as Dig mentions, is to buy the stock and action and have the barrels sent to a Registered Firearms Dealer for repair. Marry the lot together and have the gun sorted and re-proofed. Dig is a RFD so can legally take them in without breaking the law. I have to skirt around it by the above method but it is often a way of getting a bargin and making a small profit. This has to be weighed against the risk though. Lagopus.....

I have never had a problem in buying out of proof (hammer) guns privately. I was under the impression that only the vendor was breaking the rules by offering them for sale - have I got this screwed up ?

I and I suspect others here would be interested in the specifics in regard to your unfortunate burst barrel experience.
Jim

Lagopus mentions buying a gun one thousandth out of proof, suggesting that it may have been drilled out as much as ten thousandths. What is worse, a quarter of an inch at the forcing cone or ten thousandths from the forcing cone to the choke? To take metal out of a barrel to shoot more powerful shells makes no sense to me, especially after Sherman Bell's testing shows us that a quarter inch more shell doesn't change pressure enough to worry about. A 2 3/4" chamber in a gun proved for 2 1/2" shells shows me that the gun was not only owned by an idiot at one time, it was also worked on by an idiot. I, personally would not want to own it unless it was really underpriced.