I've been a member for over a decade, thought that I was proficient in using Google, but I still can't seem to find a straight answer and would like to ask the experienced members here. And I thought of asking this in the Pistol Brace Amnesty thread but didn't want to muddy the discussion there.
If you buy a new stripped AR lower, build it into an AR pistol with no brace, do you need to file anything with the ATF?