98% of the brass look like this!! I been shooting for 40 years and rarely do I see it. I only had one pistol do this on my casings it was a T PT99 and I had it looked at.. Gunsmith said it was unlocking to early do to weak recoil spring.. He was right 2 lbs more made lock up perfect.. No more primer issus.. The gun is unlocking before the firing pin has a chance to return.. I seen perfect primers marks left on rounds even with older guns that don't incorporate a firing pin inertia spring.. None of my beach locking auto leave this mark. Guess lockup timing is not that important! G