I think this is not my first. Why does the short barrel rifle (SBR) even exist as a category? Because handguns were supposed to be part of the NFA, instead of mufflers. The bill was meant to keep people from putting a shoulder stock on a handgun and calling it a rifle. The removal of handguns from the bill left a regulatory nightmare.
If they are serious about reforming gun laws, SBRs need to be put back on the table. Along with supressors. Gun bans, too. Just think of all the cash the government would get if they could tax new autos. Nationwide carry would be a start, with no local preemption.