Reading the existing machinegun law they say it is illegal to manufacture a gun that can easily be made automatic.  Doesn't that mean once they created the "bump stop" which allows the gun to fire automatically all the guns they fit became illegal?  I think after 22,000+ lawsuits I see coming the gun manufacturers are going to have a CTJ moment on this.  I would find they allowed a machinegun to be knowingly manufactured on several of today's discovered guns, look at the guns he used.  There are fortunes to be made against both the gun makers and bump stop makers.