Does the trigger fail to reset when cycling the gun empty? If yes, I would look for dirt or debris even metal chips or filings in the action. Disassembly and clean to correct. I've encountered several new, unfired S&W revolvers with metal filings and chips inside the action.

If the action does dot cycle correctly with empties in the chambers or during live firing, I would check for excess endshake and rubbing at the barrel-to-cylinder gap. The inability to cock SA and failure of trigger to reset describes either debris in the action, or something else that is interfering with the action cycling.