My neighbor gave me his 50 cal T/C Hawken barrel. He tried to remove the clean out screw, by the caplock nipple. It wouldn't come out, so he tried to drill it out, with no luck. Anyhow after me trying, using Kroil, an easy out, and some acetylene, it is frozen still. 50 years of black powder fouling, has it in there solid. I was hoping to rethread, and install a new plug. Is the factory thread an 8-32 or a 10-32, or something else? I guess if I have to, I can make it any size I want.