BATF won't let me have an M1A1? And I've got a place to play with one! $#%$@#!
Jeff, the main reason for worrying with MOA is for "long range" rifle accuracy, generally looked at as 100 yards and on out (older days) to today's 400 yards or so on to 1,000 yards.
Nothing would keep you from using MOA in talking about handgun-accuracy. Since few people duplicate Elmer Keith's accomplishments--or try to--it's not really germane to the discussion. Look in our forum on handguns, and folks talk about an inch or two at 50 yards for group size for accurate pistols, with a few shooting into half that size. I guesss it's a "why bother?" sort of thing...
Now, some of the stuff going on with the TC world is "a whole other story" from the revolver and pistol world.
Historically, MOA is a rifleman's term...
Hope all this ancient history helps. Like a lot of stuff in the world of shooting, it's inherited conventions...[What am I, the History Channel? :-)]