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Jun 14th, 2026
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Joined: Jun 2026
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Boxlock

Joined: Jun 2026
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Hello!

This is my first post, I’m hoping someone can help me solve some mysteries by helping to decode and interpret some of the proof marks and other markings on a very interesting antique shotgun from across the pond. I’m not sure how to attach pictures to the post from my phone, I’m happy to email pictures if that would help with identification.

It’s a hammered, side by side, cartridge shotgun, with 30” Damascus barrels. It appears to be of higher quality and has lots of engraving. It’s marked “A. Allan. Glasgow.” on the top rib of the barrels.

I took off the barrels and using the Standard Directory of Proof Marks, was able to recognize provisional proof marks from Birmingham, and “NOT FOR BALL” which helps date it between 1875 and 1887. It appears that the barrels get larger at the muzzle as it is marked: “13B” and “14M”, which I believe are for bore and muzzle measurements. I’m I correct in thinking that 13 would be the gauge of the barrels for ammunition selection? The underside of the barrel near the proof marks is also normally where I look to verify the gauge, and this one is clearly marked “13”. I was able to find a few examples of antique guns that were 13ga but they were muzzle loaders or breach loading pin-fire. Am I correct in thinking that 13ga is rare? I wasn’t able to find an antique ammo supplier yet (or even a company that makes brass hulls) for 13ga.

There was also a marking “J.A” on the barrels near the proof marks which I was able to determine is Joseph Asbury, of Birmingham.

This is the first antique Scottish shotgun that I’ve come across so it was an easy decision to purchase it and give it the attention it deserves.

Any help with additional information or knowledge would be greatly appreciated!!

Thank you!

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Presumably chambered for 12g.
13b and 14 muzzle are pretty normal dimensions for a nominal 12g shotgun. With bore, the higher the number, the smaller the diameter, for it is determined by the number of lead spheres of that diameter to the pound, so the muzzle has a smaller diameter than the bore; the bore is smaller than the chamber. 16, 20, 28 etc are getting smaller; 10, 8 and 4 are getting bigger... a hypothetical 1b would be the diameter of a single 1lb lead ball.

1 member likes this: Geoff Roznak
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Cadet,

Thanks, I just misspoke on the muzzle vs. bore part. Was it common for the guns to be marked for one particular gauge but intended for a different gauge?

Thanks!

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Your are correct regarding the proof marks

[Linked Image from photos.smugmug.com]

'13B' is the bore measurement. Fractions were not used until after 1887 so the bore could be .710" to .728". '13' is not at all uncommon since it could represent a just slightly undersized 12g bore, standard being .729".
'14M' is the muzzle measurement of .693" to .709".
So the bore and choke need to be measured.

Lots of information regarding the maker here
https://www.doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=339909
and
https://doublegunshop.com/forums/ubbthreads.php?ubb=showflat&Number=503991

1 member likes this: Geoff Roznak
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Now, now, now.
It could entirely be an overbored (as many of them were) 14 gauge. They were not rare at the time. Only faded out in the 20th century.

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When one hears hoofbeats, it is probably not a zebra.
Chamber dimensions would settle the issue.
The entrance to the chambers of c. 1900 12g U.S. doubles is usually .809” -.812”, tapering to .795” - .798”.
14g is .775" tapering to .763"
If a 12g shell fits in the chamber, it's not a 14g.

2 members like this: Geoff Roznak, Carcano
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As others have stated have the bore measured. Further measure the chambers. It was common on many guns chambered for 12ga cartridges in the days of cork, paper, or felt wads to be bored tighter to give a better seal.

A 13 ga chamber would be rare, but it is likely a 12 chamber with 13 bore

I have several 13/1 guns which handle 2 1/2 12ga loads w plastic wads without issue.


Michael Dittamo
Topeka, KS
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I had one 12 gauge with a tighter I want to say 13/1 (measuring around .719) right barrel that a plastic wad from a low pressure "vintager" shell got stuck in. Good thing I checked the barrel before the next round. Otherwise, it had no issues passing 12 gauge plastic wads. I was always more attentive after that though regarding checking the barrels.

1 member likes this: Ted Schefelbein
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I had a double sxs with one barrel marked 12 and the other marked 13/1. I thought this might be a defect, but asked John Foster. He said he’s even seen Boss doubles marked the same way , different bores on each barrel. That was a relief.

1 member likes this: Geoff Roznak

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