I would definitely contact Bushmaster first and see if they will hook you up with parts before you buy. I have a Predator and have had zero issues with any and all types of ammo, so unless you just got a bad batch of ammo, I don't think that's the problem. As was recommended, I would check the pin channel and then spring. Don't give up on it... mine shoots sub .5 MOA with 55 gr Sierra HP's loaded hot. I love it.