It apparently doesn't in one of the areas of which I have a high level interest. The ATF is constantly changing their mind on what a machine gun is, and if it is one, it is a strict liability crime.

Not long ago a guy was put in jail for creating business-card sized metal sheets with the image of a 'lightning link' (machinegun conversion device) on it. Not the actual device, just a picture of it etched <0.001" into the metal. Clearly just art, and even when the ATF cut it out they could not get it function as a machine gun. They gave it to an actual machinist, and even after a day he could not get it to function as a machine gun. They could only get it to do anything by literally jamming it into the gun and making it do hammer follow, which every AR-15 can do with the parts already in it.

Up until the guy was convicted I don't think anyone had any idea a picture of a machine gun on a metal card was a machine gun. They even convicted the guy advertising it, who never as far as I know actually distributed one.

Meanwhile, you can use bump-stocks as a redneck machine gun all day long.

Bumpstocks are a worthless gimmick, you can bump fire 99.9% of semi-auto guns with zero modifications or special stocks.

Are you talking about the AutoKeyCard case, Kristopher Ervin and Matthew Hoover? Ervin finally gets out of prison on 2025-05-03 and Hoover gets out on Christmas 2026.

Yes. Honestly I am astonished Ervin, the leader of that enterprise, is getting out so much sooner than Hoover who IIRC just advertised it.