Drew,
Some older Damascus barrels have the proof marks stamped on the barrel tube rather than on the barrel flats[Some suggest that at one period of time the barrel tube was the location used on U.K. guns intended for Export]. My point is; that the depth of indentation of some proof marks is greater than majority of barrel pits encountered and clearly act as potential stress raisers.Stamping proof marks requires a heavy blow,this too could cause cracks to develope.Have you seen any examples of damascus barrel failure attributable /originating at the site of the proof marks ?
