One of my damascus barreled shotguns has the markings "17.6" stamped on the bottom of the barrels. I assume this is the diameter of the barrels bore. Does anyone know what that translates to in ".0000"?

17.6 mm equals .6929"

Which likely indicates the muzzle diameter/choke. Is there a 18.4 = .724" next to it? A pic would be great



After 1924 the bore was marked and CHOKE for a muzzle constriction > 2mm = .008"

The bore dimension reads .0719 tapering to .0712 4 inches back from the muzzle. Then it is jug choked. There is also the number 13 stamped on the barrel. This gun is the "RIVAL #6" that I posted a question about on the Parker site. It has the ELG without the crown above the oval. I would post a picture if I could.

It was proofed as a 13 gauge, very common in England, in that era. Seems like it still is 13, per your measurement. But, I’m thinking the ELG mark is Belgian, not English.

Send me the photo, I’ll post it for you. My email is in my profile.

Best,
Ted

Thanks for the offer to post photos Ted but I do not have a digital camera or smart phone. It is Belgium and appears to be taper bored up to the jug choking. The 17.6 is what puzzles me if that translates to .6929