RE: Problem with Thomson center
If there is a possibility of a load being in the rifle he has a couple of choices. He can soak the barrel with water to kill the charge, and then take it to a gunsmith.
The other thing he might want to try is a Co2 charge remover. Many times that might be able to blow the thing out of the barrel and the charge if there is one. I would still water the barrel and make sure the charge is killed before I use the Co2 remover.
The other thing I have heard of people doing is rigging a nipple to a air compressor and then with a lot of air pressure built up, blow the barrel clean that way. Again, if it might be loaded water the charge. Never take a chance with a charge in the barrel. It does not take much to set them off and in his case it would be in a dangerous situation....