From Open Source Defense:

On Friday the Supreme Court struck down the ATF’s bump stock ban. Let’s break down the justices’ opinions and the implications.

Clarence Thomas writes for a 6-3 majority, and the overriding theme of his opinion is that this is not a hard case. Under the NFA, a machine gun is “any weapon which shoots, is designed to shoot, or can be readily restored to shoot, automatically more than one shot, without manual reloading, by a single function of the trigger”. Bump stocks are simply not that. That’s obvious if and only if you know how a bump stock works. Thomas explains that by explaining how an AR-15’s fire control group works.