bronko22000

Ron - I know how a torque wrench and/or driver works. But just for giggles try seating it as before with the tape then see what it takes to remove it without shooting.
That more force may just be the friction on the tape until it conforms to the interface between the breech and breech plug threads.

ronlaughlin

Installed the plug into the rifle at 40 inch pound; broke it loose from the unfired rifle at 26 inch pound.

bronko22000

Then that's pretty much what I suspected. Firing the rifle, as long as no fouling is allowed into the threads, has no effect on the force needed to loosen the BP.
Of course that is only one test run but it pretty much equals the result you got with a fired rifle.

ronlaughlin

This morning a new breech plug was tried in a different Omega. Breech plug was installed at 40 inch pound torque, and it broke loose at 20 inch pound torque; was removed from the rifle.

bronko22000

So the way I see it, torque pressure on a BP has zero effect on accuracy or the amount of torque required for removal provided no fouling entered the thread interface to cause binding of the BP.