Everybody KNOWS that it exceeds their right to regulate interstate commerce, and violates the CORE reason for the 2A, the ability of the citizenry to defend themselves against the government. The common battlefield weapons of the day CERTAINLY fall in the protection of the 2nd Amendment.
However, as others have stated, nothing outside of passing a law striking 922 (o) can be done about the way the Hughes Amendment made it into the final bill. It would have to be the perfect circumstances for a law to happen. Huge conservative majorities in Congress and a conservative President, or someone getting into some HUGE bill and sneaking it by. Even if that happened though, and it was repealed, and then the crapstorm happens, I don't know how many legislators would have the nads to stick up for it.
Also, as someone already noted, a Commerce Clause argument before SCOTUS would certainly lose, as the court has taken the position that basically EVERYTHING falls under the purview of the Commerce Clause, even intrastate purchase of something illegal. The best court argument would probably be basically a revisit of Miller, arguing that the 2A allows for weapons that in common use in the military.