I posted this on the PGCA site some time ago.
1891 Grade 3 barrels matte blued but with a potentially stunning Damascus pattern showing through had been cut, had what looked to be moderate pitting, and on checking the bore dimensions was found to have an about 1" long bulge, 1" back from the muzzle on the right; but the bore gauge showed the bulge to be only .004" and the wall thickness was .024". It took some time, but I was able to get the brass stop of the Bill Henry wall thickness gauge into the bottom of the deepest pit, and it was only .002" with a wall thickness still .029".
1903 Grade 3 D4 barrels, also blued and couldn't see the pattern. I couldn't tell if they had been hot tank blued, but they had 4 weep holes drilled in the bottom rib. The chambers had been extended from 2 5/8" to slightly more than 2 3/4" and had been honed. The left chamber minimum wall thickness was .114 but the right only .100. They were 2 frame barrels, and despite bores of .736 (also suggesting previous honing) had wall thicknesses 9" from the breech of .045" and 9" from the muzzle of .030".
My point is that (almost) NO 100 year old barrel is now as it left Meriden, and without the proper tools it is impossible to adequately evaluate the barrels. AND it takes a long time to do it right. It is not easy to eye-ball the pit, rotate the barrels in the proper position, and try to get the brass stop in the bottom of the pit.
