Hello. I just picked up a used 686 for my first revolver, but there is a problem with the cylinder. At least I think it's the cylinder. When I pull the hammer back, the cylinder spins to the first 3 chambers fine. The next 2 I have a hard time pulling the hammer all the back, and the last one I can't pull back without helping the cyl. along manually. I bought this knowing it had this problem, but it was a good deal. At least I hope it was. Any ideas what would be causing this problem? Thanks.