Not too long ago, I was in a Boston area gun store (not in the city of Boston, mind you), and the salesman told me that he could not sell any kind of AR-15 clone because of the AWB, no matter how it was configured. I said "Yeah well, what about every other gun store in MA that is selling them?" and he just shrugged and said "I can't figure out how they get away with it!"
Which store was that? Both Waltham stores and Roach's, along with Collectors and FS, all have ARs.