Since this thread is about barrel measurements and their relation to safety, would someone explain how the bore diameter measurements come into play?


The reason for my question: I've got an 1890s EM Reilly 16g with Damascus barrels made by WJ Jeffery sometime between 1927 and 1955 judging by the address (9 Golden Square). I measured the internal diameters and both barrels are smaller than the 0.663 spec of a 16g. The right barrel measures .657 throughout the length. The left barrel measures .658 except for a short section about 3" back from the muzzle where it measures .662. The diameter at the muzzle is back to .658.

I don't know what to make of the section that is .004 wider than the rest of the barrel. I would appreciate any input / education.

Jim