It's extraordinary that intelligent people believe that rendering automatic weapons illegal will have any result other than to ensure that, outside of the Police, only criminals will have automatic weapons.
Intelligent people evidently believe that the evil scumbag who murdered all those people in Las Vegas a few years ago, for instance, would somehow have been prevented from acquiring those guns!
It takes a special level of naivete, and astonishing ignorance, to imagine, should automatic weapons be banned in America, that a black market on automatic weapons wouldn't immediately erupt. Automatic weapons would be as easy to acquire as ever. How can I be so sure??
If there's enough Demand for something, the Supply will always find a way to get to the Buyer:
1 > The Mafia proved this, in the 1920s. Their power erupted because of Prohibition. That fact, alone, should convince even the most idiotic that banning guns is futile...and dangerous.
2 > If that wasn't enough, the more recent Cocaine Epidemic of the 1980s, when countless innocent people were imprisoned, despite doing no harm to others, while The Cartel's power exploded, should've awoken even the most asinine fan of The War on Drugs to its abject failure.
Whether it's Ordell Robbie, there, from Jackie Brown, or Otto Mattich, the German Arms Smuggler, some criminal or another is going to find a way to get as many automatic weapons as there is a demand for, into the hands of those who're demanding them, if they have the cash.
1 > We can either ensure that the only people who possess such weapons are The State, and criminals, thus placing ourselves entirely at the whim of both criminal scum, who would be thus entirely empowered to break into our homes, rape our Wives, and murder our children...and of the other scum, the ones who consider The State to be a tool for exerting Power over others...
2 > Or we can continue to live in a Free Society, where we have a right to protect our Lives, our Wives, our children, and our homes, from the unspeakable depredations of The Evil.