I very recently had my first problem with a breech plug siezing.
I used Knight grease as I have used on many rifles over the years and when I finished shooting only 8 or 10 rounds at the range I broke the breech plug loose. It broke loose easily, but as I backed it out it got tighter.
4 or 5 turns and it wouldn't budge any further. I took it home, removed the barrel and put it in a padded vise, then used a 7/16 socket & impact wrench to remove it. It looked like the first 4 or 5 threads closest to the breech were dry & dirty from blowback.
Second trip to the range was a repeat performance!
Third trip I tried the teflon tape (used yellow tape and applied it as Sabotloader instructs) and had no problem at all in removing the breech plug! No evidence of blowback in the threads and it came out with a nice even pressure (heavier than with grease only, but it goes in that way, too) on the breech plug wrench.
From now on I'm using tape on all my breech plugs!!!!!!!!!!!