I had a barrel in the shop a couple of weeks ago that needed the breechplug removed so I could inlet the barrel. After failing to remove the plug using conventional methods e.g. Getz style plug wrench with an 18" solid steel handle I remembered a Jerry Huddleston thread that said heat the breech area up to red hot , let it cool completely and any plug will remove easily. Sorry Jerry, not this time. I finally had to destructively remove the breechplug. Problem was, the barrel was 1.200" diameter and I could not locate a store bought plug with 3/4" threads with a 1 1/4" O.D., so a new plug was made from a piece of solid round 12L14. The barrel was chucked up in the lathe and dialed in and the damaged area parted off. Then the barrel was rethreaded and new wedding bands turned. Barrel is now inlet and back on its way to the customer.
I am not sure what caused the plug to bind. I do have a couple of theories. Could of been that the bottom thread in the barrel bound up with the lead thread of the breechplug, caused galling and bound up. Or, because the plug was a cast plug, maybe the threads were never cleaned up and they galled during installation. Anyway, I don't know and probably never will. All I can say is that this was one tight mother. Definitely a test of perseverance.
David
The below photos kind of look like beauty and the beast.
Before
After