I recently purchased a new Bushmaster C15. I jumped on it becuase of the good price I got for it. I'm "happy" with the rifle so far, but I'm having an issue. When I fire the weapon, the first 10 to 15 rounds go bang with no problem, then things go south. The rifle is failing to feed the next round. Some times the brass is bent and dosen't chamber properly. Most of the time it won't pick up the next round at all. It fires, ejects and won't chamber. I charge the weapon and it fires, and fails to feed. I have tried 7 different mags, three types of ammo, and two different grain weights. I'm about to pull my hair out. The only functioning part I have change is the buffer tube, and even before that I had this issue. My army buddy's just bitch about the AR being picky and offer no realy help. Does anyone out there have and idea how I can fix this issue?