doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Lets talk proofs!

Can any one tell me whats going on here?

http://www.shotguns.se/html/uk.html

Birmingham 12 gauge 2 1/2 inch chambers

Choked bores

Has been reproofed (Crown R)
Reproof date 1992 (Crossed swords TC1)

Has original date code and reproof date code

850 Bar is the proof pressure

What would the 18-1 and 18-7 represent? And the 14 and 1?

The 18.1 & 18.7 are bore diameters in mm. Although very faint it appears to me the 1? is also a 14. This would have been the gauge of the bores at original proof. 14 gauge = to .693" 14/1 would have been .701" so the bore would have been between those two dimensions when proofed. Obviously, the 18.1 bore has been enlarged a bit & the 18.7 one a great amount. They were, however, re-proofed as enlarged.

Interesting, its on a 12ga Tolley, do you think they made a 14ga?

Please look at BL1 and BL2 on the proof chart

https://www.vintageguns.co.uk/articles/proof-sizes/

http://www.hallowellco.com/bore_size_chart.htm

If can make out the original date code, that would
be of help

Mike

Only the left tube had choke originally. Right would have been cylinder.
18.1mm = .7125"
18.7mm = .736"

Hard to imagine it was a 14 bore originally! I would check the wall thickness in the left tube.

Skeetx: Yes, I can see the reproof code front of left barrel flat but where are seeing the original proof code? There were no Birmingham proof codes until the 1920's and London didn't introduce them until 1972. Are you mistaking the Birmingham View and Definitive proof marks for date code stamps? These were discontinued in 1904, the Diamond with the nominal Chamber size introduced in 1887 so the best you are going to get from the original proof marks is 1887-1904.
I see quite a few old 12b shotguns with tubes proofed at 14. These tend to be at the cheaper end of the quality range but that is not a hard rule. I have always assumed that this may have been a way of saving a few pennies: one can use a smaller tube blank if one bores a smaller hole up it AND get good thick walls. Probably a majority of the Birmingham gun trade were producing guns down to a price, not up to a standard, so every penny counted.

There are proof codes before the 1920s
There are no date codes before the 1920s

I do agree with you that this gun was made way before
the 1920s

The BNP Crown has been used since 1954 and I think the
entire proof stings was added at reproof.

There are three proof date codes, I can only read one at this time

Mike

Right, and based on what Miller had mentioned I was making the assumption it had been honed (they are damascus) and reproofed at the larger 18.1 and 18.7mm diameters, so the 14/1 was a bit of a mystery.