Believe it or not the NRA helped push the FOPA '86 through and endorsed it. One of the main things it did was to get some protections into the law for gun owners regarding the interstate transportation of firearms. The MG ban was suppossed to be a poison pill added by a few democrats to the original bill, but the NRA thought they could get that provision cleared up later (either in conference committee or by a later bill) and continued to help push the bill into law.