From The Truth About Guns:

When the state attorneys general sued to stop the rules from taking effect over unfounded concerns with 3D printing and a conflation of export controls and domestic gun control laws, NSSF led the fight to allow the final rules to take effect by moving to intervene in the case. Our brief focused on the scope of the remedy (injunction) the court might enter, should the court determine that one was warranted on the merits.