Headspace was set with a go/no go gauge. It is a match chamber. Headspace was set with very little tolerance between go and no go (0.002") per jim briggs recommendation. My dies are set up to bump the shoulder back 0.002" from fired lapua brass. My dies size any brass lapua or cheap stuff fired from my savage without any problems. If anything I need to check the headspace on military rifles. I think the issue is the brass is blown out from the opened chamber of the military rifles. They may have just been stretched beyond what my dies will size without modifying the dies, or the brass is spring back too much after sizing and need to be annealed. Either way it is a moot point as I'm just getting new brass.