Having an unstamped machine gun is literally just an issue of taxation

I'm honestly surprised that people charged with violating the NFA haven't challenged the law as cruel and unusual punishment. 10 years in federal prison for failure to pay a $200 tax? Shit, they've got nothing to lose adding it to their defense.

And those lying assholes swore in Miller it was a tax measure, not an attempt at illegal federal gun control, so they could use fedgov's own words against it (they cared just a bit more about the appearance of complying with the Constitution then; now they don't even bother).