Thanks for the feedback. I was able to get it out. I had been treating the outside of the plug a bit at a time with Kroil over the last couple of weeks, but a healthy shot down the barrel and then swabbed up against the breech plug seems to have helped.
Also, I don't have a barrel vise, but I do have a tipton vise. I put the barrel back in the stock and secured it in the tipton. Then with a socket wrench I was able to get enough grip to budge. That first little bit made a terrible sound and didn't budge much. But from there it got better and came wright out. Relieved.
