What is the cause of pierced primers? I have a RRA 16" Carbine with the 233 Wylde chamber. For some reason It will pierce about 3 to 5 rounds out of 50. the primers are Not Flat or really showing High pressure. It does it with Hornady, Remington, Winchester, and Fiochi. It does not do it with PMC Or PPU. that I have noticed. I changed out Fireing pins thinking maybe that was it. I have noticed it does it more with about 5 to 6 rounds down the tube. Could the chamber being hot raise the pressure enough to cause this? Thank you for any insite you could give. I would hate to have to send the upper back to RRA.