Add some dry-slide or graphite lube to the front bolt area where the lugs rotate and lock into the receiver. Mini-14's are famous for this area being very tight. In fact the slide will seize in the closed position after sitting for a while if it isn't kept well lubricated in this area. I bet if you lube this area the bolt will rotate fully into battery and fire correctly.
By the way, letting the bolt slam closed on a Garand style action like that on the Mini-14 is not a bad thing. They are built for that.
Fear is a Reaction..............Courage is a Decision
Last edited by Snakedriver; 02-27-2011 at 12:35 AM.