The little screw that holds the piece on the cocking lever was loose on mine yesterday. As I was cocking, the screw came out and the gun fired, made me say what the xxxx just happened. Luck was with me as I found both parts and with a little filling on the first couple threads I was able to reassemble and keep on shooting. You may want to check that part every once and a while. I didn't lock tite mine, just snugged it down tight