Folks, I'M new to the forum. Was given a custom AR from a buddy. Yeah I know, nice gift. It fires 5.45x39. I took it out to the range for the first time and had a blast. Only problem was I had a 30% fail to fire rate. All the cartridges that failed to fire had dimples in the primer and the primer looks like it was literally bent in to the casing. I can't do a search yet do to the 10 post limit, but what I've seen is that the trigger spring sometimes doesn't provide enough force to ignite the primer. The bullets were silver bear. A guy at the range thought it was the ammo because the primers were well dimpled. Any suggestions?