Thank you again. LOL. If I fa10 100% ar lowers, the assumption by the AG would be that I built them into guns capable of firing a bullet. Correct?
That would probably be a good assumption but here is where the modern sporting rifle is unique: You could have 100 complete lowers and only a single upper. These could easily be switched and swapped amongst them but per the ATF only the lower is the firearm. The MA definition of a completed firearm is at odds with the actual composition of the modern sporting rifle.