[jlcx]

"The NFA proved very effective at reducing (eliminating, actually) murders committed with automatic weapons on the registry"

That might be a bit too optimistic about the NFA. The NFA likely did reduce the possession and use of machine guns, but one reason for that is that people could just buy semi-automatics instead without dealing with the NFA-related headache, which suited most people just fine. Also, a lot of the crimes committed with NFA-regulated weapons prior to passage of the NFA were related to Prohibition, weren't they?