Too little neck tension? Virgin Lapua Brass? Cratered Primers

[CA_Shooter]

I wanted to give an update for anyone that may have this issue in the future and may find this thread useful. Thank you everyone for the thoughtful replies.

I did another round of testing today and did not have any cratered primers. I had 1 or 2 with a very very slight ring that you can see if you squint.

What I changed this time vs the last when I was cratering primers:

Craters:
•Virgin Lapua Brass, which is very short
•extremely light neck tension. 5‐10 PSI with my arbor press
•jumped to .0200

Today, no craters:
•once fired lapua brass, bump sized to .002. I only used brass that was bump sized .002 under my chamber. Brass that didn't grow to this size was not used for testing today.
•tighter neck tension. 25-40 PSI with my arbor press
•jumped to .0790

It seems that what was causing the craters was the virgin lapua brass because it had a lot of room to grow and the cases that cratered grew the entire size of my chamber on the first firing.

 

[CA_Shooter]

I want to give a final update for this thread. The issue turned out to be that the firing pin hole on the bolt was too big, which was cratering and piercing primers.

Big thanks to @carlsbad for fixing my bolt. Issue is now gone after he bushed the bolt. Here is an image of primers shot today. None cratered or pierced