[ithacaartist]

This dent is puzzling, indeed. Looking at the cross-sectional drawings, this area of the breech block looks pretty beefy, despite the tapered relief hole/relief on the inside for the f.p. If the tip of the firing pin conforms to the shape of the hole, then the force of impact is transferred over a rather broad area. For a breech block to become pooched out around the hole for the striker's tip, it would be the corresponding area on the striker itself that would have to be the point of contact/impact--and the rest of this mating would need to not touch/hit. This is the only way I could see for significant material around the hole to be displaced/peened--by this area, alone, absorbing the bulk of the blow. And if the depression around this one's hole was caused by a punch, in an attempt to correct the former, where in heck does all the material go? How frequently is this deformation of the breech block face encountered?