I've been test driving a model 12 for a few outings, and have had issues with the bolt not closing, and or not wanting to come back after failing to lock up. It did it today, and after cussing it, and some muscle I got it open and the shell out. Afterwards; I tried just the bolt, and even it wouldn't close on an empty chamber. The gun also has a habit of the trigger locking up. Meaning even the blade in the trigger wouldn't budge. Cycle the bolt again, and it has fired ok.

Turned out the screw on the back of the bolt was loose by a few threads. Tightened it up snug, and it fed ok from there on out, but the trigger did lock up again about 10 rds later. How tight is that screw on the rear of the bolt supposed to be? Any idea why the trigger locks up now and then? My friend had originally told me he thought it threw a flyer on the first shot after the trigger locked, but now says he's unsure if it was just the aggravation of getting off the gun and cocking it again that made him pull the shot.