This was a problem with some early breech loaders where the angle was at 90 degrees. Cracking occurred either at Proof or after prolonged use. It was soon understood that it could be cured by a radius at the point between the breech face and the action flats. I have a very early hammer gun with a sharp cut off by Turner of Reading. It's not shown any sign of failure yet although I very seldom use it. I would never think of trying to submit it to Nitro Proof. Firing the gun produces a downwards flip of the barrels which puts strain at that point and the reason some guns have top bolts. Lagopus.....
