Quote Originally Posted by Dirk
A little excessive head space doesn't blow out primers like that. It might push them back and then when the pressure builds it slams the case back against the bolt so the primer re-seats and gets very flat. You show all the indications of a pressure problem.
I agree with you Dirk. I'd be scrubbing the gap space and the first inch of so of the bore with acetone, acetone-ATF mix, Seafoam, Iosso or GM T.E.C. especially since its a used '99 vintage rifle. More than likely it never had the chamber cleaned and might be the very reason it was on the used rack.

Since the problem PROGRESSIVELY got worse with subsequent shots it has every indication of a carbon buildup.

Bill