Unlawful, but not unconstitutional?
I can understand allowing pistols, rifles and shotguns. However, would you prefer some gang-bangers opening fire in your neighborhood with a 12 round 9mm Glock, or a fully automatic weapon?
One could argue that a 'need' for a fully automatic weapon isn't valid. However, I see no problem with the semi-automatics. The present system (Class 3 Federal Firearms Permit) for fully automatic weapons has worked very well since the 1940's.