I have a question for Armalite AR10 owners. A buddy of mine just picked up a used AR10t that has a custom barrel on it and we noticed that after cleaning it, it will not close up without cocking the hammer first or it hits the firing pin on the backside. I used to own one of these but I don't remember it having an issue hitting the firing pin. It appears to be headspaced properly as the bolt looks like it is fully closed. Any ideas?