Took my gap semi 308 ar out to sniper qualification and began to have issues. It's a 18" barrel which I always run supressed (.308 surefire 762ss can) with an adjustable gas block and hyd buffer. It began piercing primers on me with factory Hornaday tap match ammo. About 30% looked normal, 30 % deeper than normal indents, and 30% actually had a hole through the primer and the pin punched out a nice disk piece of metal.
The gun does need to be cleaned, and it began to have a few chambering issues as well near the end (of course there could be metal fragments in the chamber now). My question is if the pierced primers could be related to the dirty chamber, or is it the ammo, or maybe a too far protruding firing pin is the suspect I should check? I didn't notice any other signs of high pressure.
I have not noticed this before with any ammo (but this is a new case), rifle has about 2500 rounds through it. My plan is to clean it real well and run to the range tomorrow before work, try the tap again, and also some Fed GMM I have. If both ammo types still show piercing the primers in a clean rifle, I guess I should change out the firing pin?