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

Note that at this point in time chamber length was not marked per se. However the 1� oz maximum load for the shot does indeed indicate a 2 3/4 inch chamber. The nominal 2�" chambered game guns carried a 1 1/8 oz maximum mark.

As with many of these topics, nothing is quite so cut and dried.
The ledger shows that the chambers were 2 3/4" and I would take that as fact but the 1 1/4oz. Max. does not necessarily mean that all chambers with that proof were 2 3/4". There are many British guns from that time with 1 1/4oz. proofs which have 2 1/2" chambers and 2 3/4" chambers would have been unusual.
Also, supposedly, guns with 2 3/4" chambers should have the "LC" designation under the 12 in the diamond indicating a "Long Chamber" but I rarely seem to see that mark, even on guns with original 2 3/4" chambers.

I believe the LC mark is only for chambers longer than 2 3/4".

Pressures for American factory loads were increased in the 20's, when Western's then-new Super X load appeared. SAAMI did not exist until the 20's, but generally speaking, American factory loads were lower pressure prior to that time. I've read from one source that the Super X increased service pressure by about 1,000 psi. In any case, I would not shoot modern American factory loads (other than RST's etc) in a Grant that's over a century old.

Larry is right, the LC mark did not begin with chambers less than 3" in length. W W Greener definitely speaks of 2 3/4" shells being in common use for both Pigeon & Wildfowl guns. The common proof for a 2�" game gun was for 1 1/8oz, that for the 2 3/4" guns 1� oz. A 2�" chambered gun carrying a 1� oz [roof would have been by special request "Only" & would be the much more "UNcommon" proof.

Thanks again for that information... I have been shooting 2 3/4 at one ounce or 3/4 ounce loads...but you are sure I should abandon that and shoot the RST...RST makes 2 3/4 as well...I will think about all this...here is the history for the Grant which has me wondering further...the chambers do measure out just right at 2 3/4. It seems the orginal owner was also the guy who had the work done at Boss...so I do not know if The later Jones owner did anything to it even though it states the guns stayed together till the 1940's.

Condor;
I believe the 2 3/4" chambered guns of this era carried the equivelent of a 3� ton proof. This would translate to about 9800 PSI. It is noted this is less than SAAMI spec shells & is around 1,000 PSI below modern day CIP "Standard" which was listed as 740 BAR (about 10,730 PSI).
Personally I would be much more concerned with the increased pounding on the gun overall from heavy loads than the actual pressure increase.

Ok...understood...thanks again...

That's the standard 2 3/4" proof mark applied between 1896 and 1904; so correct date for your gun. This was later translated to the 3 1/4 Tons per Square inch proof mark. Not nessessarily for American cartridges, just the British mark for 2 3/4" chambered guns in that period. Lagopus.....

Right, I stand corrected! This explains why I never see it...
Perhaps it is my own cognitive bias but I seem to observe that most guns from this era bearing the 1 1/4oz. proof marks are 2 1/2" guns and not 2 3/4".

Lagopus is correct. LC is a 3" chambering and the 1 1/4oz stamp shows a 2 3/4" chambering for the heavier cartridge.