OK, this was weird... my son shooting my M&P Pro 9mm, using some 115gr plated over 3.8 Clays with either Federal or Winchester primers. *Might* have been magnum pistol primers, those were all I had for a bit. ANYWAY, we're about 70 rounds in, and there's a sound like a squib load (yeah, I know 1st hand, as I've made some by accident). So we check, and the bullet hasn't even come out of crimp! Looked at the primer, and the outer base is blown away! Only the center is left. Still fully seated. Get home & pull the bullet, there's a full load of powder, nothing blocking the primer flash hole. Deprimed, and only 1 primer came out (thought maybe somehow I'd missed the deprime & squashed a 2nd in the hole... nope.)
Any ideas?
Any ideas?