Hey guys I have a question on bolts. I read the BCG PiP for the M4 has been cancelled because none of the entrants offered any improvements, so this got me curious about why they did not offer any extended life and why bolts seem to break so early.

I did some searching but could not find anything pertaining to my question.

From what I have read the AR-15 bolt in an M4 under heavy firing schedules is generally good for 6-10,000 rounds, while bolts on piston guns seem to be good for 20,000 or so.

Im wondering what makes the difference? The bolt even in piston AR-15's seems to be made the exact same way as the standard bolt, but they seem to last longer.

Is this a material difference, the heat generated from the DI system or is it a little bit of both?