The simple fact that full-auto guns aren't being illegally manufactured, despite the ease with which that could be done, indicates how misguied the "assault weapon" argument is.
With a small, but modern machine shop and 2-4 people, hundreds of guns a week could be produced.
But then, there's the penalty....from what I remember it's $250K fine and 5 years of A$$-Bangin' jail time...quite a deterent....