Never had a primer leak issue until recent. Using all Winchester WLR primers. They eat a bolt face quick like an acetylene torch. I have heard a few reasons why but do not know for sure.

1. Loose primer pocket
2. Primer was damaged as it was "seated" into the case
3. Dirty primer pocket didn't allow primer to be seated correctly.

I have had this happen in 3 firearms. I contacted Winchester and each time they offer a rebate to purchase new primers but never have covered the damage to the bolt as of yet? I will never use Winchester Primers once I run out of these.