Those small pins that hold the firing pin in place can be very difficult to remove and expensive to repair if things go wrong in removing them. I've been down the expensive repair route. I had a my nitro disassembled for a restoration effort and in the process the gunsmith twisted the head off the small screw. He then went to drill his mistake out and got off center. I finally got ahold of the action sent it to California where they used a small 'tap blaster' to clear the screw and then fit the action with a new bushing to hold the small pin ($200). Had the gun not been is such good condition it would have become a wall hanger.
