doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com British Proof Mark Assistance

Ok gentleman, tell me what I have here. This is a British hammer gun circa 1871. The barrels are jug choked equivalent to Skeet/IC according to the dealer. My guess is that it was BP reproofed after the jug choking job. How do you read the marks?

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There are better men at this then I, but I think it has been reproofed as there are repetitive proof marks on the barrel flats. It looks like it was originally proofed in London, then later reproofed in Birmingham

You've got a bunch of different proofmarks--original and reproof (or reproofs?) The V and CP under a crown are likely original London proofmarks, as is the 12. The small mark next to the .740 in the lower left is a Birmingham mark from 1921-41. The BP under that particular crown dates from 1904-54. The 1 1/8 oz dates from 1896-1954. The 2 1/2" dates from 1925-89, but the .740" only from 54-89--and from that period there should also be something like 3 tons. Putting all of that together, looks to me like there must have been two reproofs: The first between 1921-41, and the second from 54-89--although I can't account for the missing "tons" proofmark. And I think also a BNP under a crown along with the "tons". Maybe others can help unravel the mystery.

Larry the 3 Tons mark will be absent as the re-proof was for Black Powder. First proved in London for BP then recently re-proved for BP in Birmingham. They changed the BP re-proof mark a few times in the last few years. I think the last one I had re-proofed with those marks was sometime in the 1990's. Can't quite read the date code in the crossed sceptre mark but if it's 'RB' then that is 1966. The 3 Drams 1 1/8th. ounce is the maximum service charge. Note: Not Nitro! Lagopus.....

Note also that 12/1 kicks in at a bore of .740" diameter. Thus if it will accept a .740" plug gage to the required depth, 9" I believe, it would be "Out of Proof" for the original 12 marking. Assuming the .740" was stamped at the time of the later 3 - 1 1/8 black powder proof it would of course be In Proof for that load.

Regardless of proof I think 3dram of black powder and 1 1/8 oz is too heavy a load for a gun of this age. I would think a limit of 2 3/4 dram BP and 1 oz would be a wiser load. Generally nitro powders generate twice pressure of black powders, but there is such a variance in burn rates and chamber pressures between the various nitro powders a little more research would be time well spent.

Thank you all for the advice. I will confirm "RB" when I get home this evening, but thanks for deciphering the 1966 proof associated with that code.

I also wonder about the age of these barrels and shooting nitro shells in them, which is my desire. The min walls are .025/.028 which appear to be at the end of the barrel where jug-choked. Elsewhere they measure min .030+. My intentions are to shoot low pressure Nitro and I would appreciate any advice on these intended loads (from an earlier thread) in comparison to comparable BP loads:

12g 2 1/2' and 2 5/8' chambers were proved for a maximum service load of 3 1/4 Dram with 1 1/4 oz. shot. (1220 fps); the "standard" load was 1 1/8 oz. 3 Dram

12g Black Powder pressure
1 1/8 oz. 3 Drams (1200 fps) of DuPont FFFg (82 grains) was about 5000 psi.
1 1/8 oz. 3 Drams Curtis & Harvey�s No. 4, T.S. (82 grains; somewhat similar but not equivalent to medium grain FFg) was about 6500 psi.

RST 12g 2 1/2" shells; fps and psi
Ultra Lite 3/4 oz., 1125, 4400
Falcon Lite 7/8 oz., 1200, 5400
Maxi Lite 1 oz., 1125, 5700

Just checked the date code with the crossed swords and it is a little difficult to decipher. My best read is that it is Z on the left and B on the right with a 2 under the crossed swords. 1974?

Wouldn't be 1974. A different style date code was used after WWII.

Lagopus, thanks for the correction on the absence of the "tons" mark.

I've got ZB down as 1974 taken from Nigel Brown's book.

I'll agree that 3 Drams plus 1 1/8th. ounce is a meaty load. 2 3/4 Dram and 1 ounce shoots sweet and you will find it all you need. For clays I just use 2 1/2 Dram to 7/8th. ounce. That stamping is for the Maximum service load rather than the recommended one.

Owen, two things to consider. If someone sends in a BP proof gun for re-proof they will just re-proof for BP unless Nitro Proof is specified. It may be that the Proof House upon examination did not consider it would pass re-proof for Nitro and would recommend that it only be submitted for BP proof. They will offer guidance and support on the decision which they base on over 200 years of experience. I think the 'Scotty' doctrine here may be appropriate; 'I dinna like to push her Jim she may blow'. Lagopus.....