This GooToob
VIDEO (5:09) by VICE is about a "reporter" who interviews a former ATF guy who helped draft the exception for the Slidefire stock. Technically, you are still only pressing the trigger one time at a time. He then brings the reporter to a range where they shoot some rounds then practice shooting rapid fire WITHOUT a "bumpstock" but by merely holding the gun in a way that allows it to recoil against a stiff finger. With practice, they were shooting "automatically" quite efficiently! Not a bad video and not political at all, really...
So what next? Outlawing fingers so you cant squeeze a trigger?