doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Info on proof marks for London bore rifles?

Can anyone point me towards a guide to proof marks on London-proofed gauge or bore rifles? I'm confused by the marks on a steel barreled 20 gauge that's proofed on the barrels and not the flats with London proofs.

Between the viewing proof and the definitive proof, there's a "39" marked on the barrel. No other markings for gauge or caliber.

Any resources you can share or an interpretation?

(I also posted this in the gauge rifles forum - cross posted here too, hope that's ok.)

Thanks,
CJF

CJF;
Has this gun possibly had the barrels opened to a 20 gauge from a smaller rifle. That 39 would seem to be a "Gauge" mark. 39 gauge equates to .492" in diameter. This would have been marked per bore diameter, not including rifling grooves. Did it perhaps start life as one of the .50 caliber black powder rifles?
Offhand I do not recall the date that British proof houses discontinued using the gauge mark on rifles & went to actual measurements.

Hi 2-piper,

I was wondering that myself. I'm working only from someone else's pictures right now. Barrel wall thickness at muzzles looks right for this to have been originally a 20 gauge...they appear quite stout now at .615.Would be surprised if they'd originally been .123 thicker!

But I agree. 39 gauge makes sense, and if this was opened up, it would have seemed to make sense that would have been in the UK after they cracked down on rifle ownership (like all the .410 rooks out there.) But I don't see any new proofs.

I'm in deeper water here than I'm used to.

CJF