The pistol brace rule was not overturned on 2A grounds. It was overturned because the ATF didn't dance the right steps to satisfy the APA. The court also found (quoting):
"the adaptation of the Final Rule was arbitrary and capricious for two reasons. First, the Defendants did not provide a detailed justification for their reversal of the agency's longstanding position. And second, the Final Rule's standards are impermissibly vague."
There's nothing which prevents the ATF from trying again. Even worse, if the Feds can convince a trier of fact beyond a reasonable doubt that a braced pistol was "designed or redesigned, made or remade, and intended to be fired from the shoulder" both the maker of the weapon and the user of the weapon can be convicted under the NFA despite the rule being struck down.
It's barely possible that a favorable ruling on an AWB case would be broad enough to invalidate sections of the NFA. But frankly, I don't see that happening. The most likely outcome is that Snope has no impact on NFA at all.
I believe it'll take a different case to strike down suppressor laws, since unlike Massachusetts, Maryland law doesn't prohibit them. Nor is a $200 tax stamp the barrier to ownership that it once was.
