Gosh, I hate to go against the grain, but I have found with both of the A&H's and my Remington that if I do tighten the breech plug up against the rim in the barrel snuggly, not tight but snug, then I really do not have a problem getting them out. I do not loosen them at the range either. It seems to me that if the face of the breech is up against the face of the barrel flange and the antisieze material what ever it is filling the threads of the BP blow-back should be at the minimum. So far I have really been lucky I guess.
I do know that I DO have to clean the BP threads and the recieving threads to maintain a the proper seal and seating of the mating parts.
During an outing to the range I may fire 25-40 rounds, come home remove the nipple then the breech, I must admit sometimes it starts a little stiff, nothing major. When I really have a problem is when I do not get the BP snug up against the flange, usually because of dirty threads.