I have ran maybe 500 rounds through my ar556 and never had any problems only one jam. That was when I ran some ammo from the range I wanna say it was Mag Tech .556. Didn't seem to take it very well I ran 100 rounds and took it home to do my normal cleaning and that's when I noticed the scratches/gouges inside my bolt. Never seen that before and I'm not sure what caused it because I clean and lube my ar after every time after the range. Not sure if it's a big deal but I'm hesitant to take it out let me know some insight please!!