It is with great trepidation that I ask this question of this learned body, but after following the nearby discussion of Mauser lug set-back and heat treatment I am a bit confused. The assumption seems to be that all Mausers were case hardened. I have a yugo M24 which I am sure was through hardened. This is only based on the "feel" of drilling it, but it sure wasen't cased. Felt like low to mid thirtys, RC, all the way through. Tomorrow I will try the dial indicator trick to check for lug set back, but I did'nt notice any putting the rifle together.