Interesting. My 500 S&W is locked up and I think the little lock on the side is the problem. First I have never used the lock so know nothing about the lock. Heres the story. Was out on a four wheeler and cracked off a round. I opened the cylinder replaced the spent round and closed the cylinder. Got home and attempted to unload the weapon and find that I can't. No function at all. Can't move the cylinder catch, can't pull hammer back and can't pull the trigger. I visually check the barrel cylinder gap and the cylinder frame gap all seems well there. Tried thumping the cylinder hard with my hand and accomplished nothing. I can however shake the dun and it now rattles. Here's the question. Can that little lock in the gun come loose and lock up the action? Can I take the gun apart and repair/remove the lock? Has this happened to anyone else? Any help suggestions are greatly appreciated.