English Rebel, 13 indicates that the original bore diameter was .710. .719 is the bore diameter as reproofed. As gunman says, the original proof is in the 1904-25 period. This is a bit tricky, but 1925-54, the gun would show chamber length. This one does, but the chamber length stamp of 2 1/2" and the 3 tons stamp are so similar that it's obvious they're from the same set of proof stamps, which are the later ones. So with no chamber length stamp among the original marks, that means it does not fall in the 25-54 perid.
