Fully automatic assault rifles, anti-aircraft guns (that still operate), anti-aircraft missiles (that still operate), land mines over a certain size, or any Comp B. Those are on the naughty list.

There’s a whole community of folks building semi-automatic auto-return triggers that are “technically” semi automatic, but with just a gentle squeeze, fire off another. If you maintain that grip, the return mechanism engages, returning the trigger to firing position, where your pressure causes it to fire again… it’s called a Forced Reset Trigger.

Sawed off shotguns, sawed off barrels in general.

My point overall was government is fine with arbitrary exceptions that would get Stan's dad going all "Oh I'm sorry, I thought this was America."