I just purchased an unfired Sharon rifle barrel in .54 cal still in the white. I need to remove the breech plug to install an H&A style UNDERHAMMER breech plug.My problem is the installed plug won't move...at all. Soaked in penetrating oil for 4 days, applied heat and ice,used a pipe wrench with four foot extension and it WON'T move.Shouldn't be rusted so I am thinking it must be soldered in place.(Ramrod pipes are all soldered on also). My question...did Sharon routinely solder plugs in or is this done later? Am going to try two propane torches to get more heat on site, or go purchase a MAPP torch to try. This is getting frustrating. Any ideas or suggestions? Thanks for your help, Bruce H