I just bought a bushmaster predator upper and took it to the range and after the first shot I had to recharge it because it didn't push another into the chamber and after a couple of rounds it jammed on me with one round almost into the chamber and one from the mag hitting the bottom of the one that was almost into the chamber. I only tried two different types of ammo, Remington .223 and Wolf 5.56 both 55 grain. Any advice on this prob would be appreciated. Peace