What’s to follow though? ATF or DoJ are not going to challenge any of the ruling, especially after this case. It’ll remain on the federal register, but stayed from enforcement indefinitely
You mean the "Brace Rule"? It is more than just injoined. It is vacated entirely. So it is as if it never happened.
Not 100% sure but I don't think it can stay on the books anywhere, if the ruling isn't challenged.
Fine by me, it was garbage law and they used illegal methods to promulgate it.
What's more likely though is that they reintroduce the rule in some other crappy incarnation that has the same practical effect, and hope it sticks the next time.
Not a lawyer but I would assume any that were registered through that mechanism are on the NFA registry. If you have your paperwork and the stamp, it is legally a registered SBR (whether you paid $200 or $0 for it). Might as well put a normal stock on it at that point.