Bolts are at least case hardened, it's probably more practical and faster to scribe an X on the bolts with a carbide tip than it is to set them up in a fixture and punch a mark on them after they've tested them, more visual too.
No need to overcomplicate something that doesn't have to be. This ain't a german gun.
No need to overcomplicate something that doesn't have to be. This ain't a german gun.
