Topic: pierced primers

[monkeywrench]

Today i was working on some .223 loads for my AR15. I started out shooting some British surplus to warm up with. Then I began shooting my own loads. After a few mags I noticed I was getting some pierced primers. Sometimes two out of ten. I was not loading hot loads. Was working up from recommended starting powder charges. What could be happening? Could there be Excessive headspace on the brass? Perhaps I pushed the shoulder back too far. I shot a half a box of federal factory loads after and no pierced primers then. I took the firing pin out and found the end is rough now. That sucks. I guess I'll be buying a new firing pin. Any ideas on where to get a new pin? The rifle has less than 500 rounds thru it.

[Spiff]

You may have a firing pin hole in the bolt that is approaching the large end of the specs, and a firing pin that is approaching the small end of the specs.

I say this because an enlarged firing pin hole (from wear) in the bolt it usually attributed to pierced primers if the load is known to be low pressure. But your rifle is new.