Hi - I was out last week and was testing several brand for best accuracy. After just over 100 rounds I had gone thru CCI-40gRNCu, and Fed Black Pack 36gHPCu and was near 35 rnds of Fed AutoMatch when I had a round blow up in my face. The bolt did not completely close, over a quarter inch open when it fired. The case blew out the side, but the bullet went forward - mostly. When I was cleaning that night, I found several tiny 'crescent shaped' shavings of lead inside the action, even around the hammer and springs. Some seemed to have copper coating so they were from either the CCI or Fed BP (both HV) since the Fed AM that blew was RNL. I had had some of the stovepipes of fired cases but that has occurred with most brands and also with my Sav-64, so doesn't seem to be an issue? I keep the action lightly lubed with silicone grease (that caught the shavings), but nothing at the chamber face. There was very little residue in that area, partly 'cause it got blown away? The blown case was too mangled to determine anything from it. Anyone have this sort of thing happen? Any suggestions as to what may have occurred?