The angle of the locking surfaces is apparently not critical as long as it is not too steep. However, when rebuilding a Krieghoff, the original angle is maintained. Of course, there are many other gun locking mechanisms that rely on very small locking surfaces, or no locking surfaces in some cases of self loading weapons. I was at Krieghoff USA last week discussing this very subject with one of the gunsmiths. He was asked if there was a jig for a vertical mill that made sure that surface was done perfectly on rebuilds. The gunsmith said that no jig was used and gunsmiths used the eye to determine when full contact was reached on both sides through the use of a file. The Krieghoff I have shot the most is 44 years old and has never had the contact surface welded or adjusted. The top latch is usually not the wearing surface, the barrel contacts being the area welded and filed into contact. None of my old Krieghoffs show any sign of being close to needing a rebuild of the locking mechanism. Two of them were built in 1974 and the other was built in 1967. The 1967 gun has been in constant all around use since I have owned it, twenty years now. Before that, it was a trap gun.
