Pierced primers on my 308 AR...

[ShooterwithNoName]

Was shooting my 308 today and had a FTF. Cycled the loaded round out and it didn't even have a mark on it from the firing pin. Pulled it all down, everything looked ok. Checked my fired brass and sure enough I had a pierced primer. Cleaned everything up, blew it out. Checked FP protrusion, it checked out OK.

Fired another round, second round got a FTF again. Ended up having one of the "cups" that punched out of the pierced primer back inside the firing pin channel. Called it a day on the 308 and packed it up until I could get it home and check it out.

The camera on this phone sucks... Here's the pierced primer:

Here's the one of the ones that fired without piercing:

So every piece of brass that wasn't pierced, was definitely on the light side and cratered. I did just put a new RRA 2 stage in and this was the first time I fired it with that trigger. I used a standard hammer spring that I had took a little tension off of, which I'm guessing is too light.

Also I was shooting IMI 147gr FMJ, just testing the function of the trigger so I didn't want to burn my FGMM... I'm pretty sure that the IMI probably has harder primer cups than most other commercial ammo like the FGMM? So I'm gonna get a new hammer spring, was thinking about getting the JP reliability set, extra power hammer/reduced power trigger.

The bolt is a JP enhanced bolt. Didn't find any damage on the bolt from the gas coming back into the bolt. The bolt would smoke after the round with the pierced primer was fired, should have been a giveaway. But it did leave the tiniest burr on the very tip of the firing pin. So now I've gotta get a new JP firing pin too. Luckily I have a spare, just have to replace the spare.

Any recommendations on extra power hammer springs? Wolff or? Any thoughts feel free...