In addition to the info Raimey provided, the numbers 118.35 is the bore(not groove or bullet)diameter expressed in gauge. They didn't start using mm measurements for this until later(around 1911-12). The crown W on the right shotgun barrel, means it is choked, but the amount of choke is not shown. The marked bore diameter is consistent with your idea that the caliber is 9.3x72R( a chamber cast would show, for sure).There are 3 different marks( in gauge)found on 9.3x72Rs, this one is often found on those with .358-.359" groove diameter. If you handload, bullets of this diameter are readily available. The 16 in a circle means the gun is chambered for 16 ga. 2 1/2-2 9/16" shells, rather than the current standard 2 3/4".
Mike
Last edited by Der Ami; 10/10/15 02:23 PM.
