The left always seems to believe that crimminals will somehow magically decide to follow a gun ban. They will stop using guns and somehow stop selling guns.
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There is no reason to think that at all.
In fact I'd expect an assault weapon ban to cause more shootings. Those who are committed to committing Mayhem, will do as they have done in Chicago for generations. Buy their weapons on the black market in the back rooms of bars, out of guy's trunks, etc. And there will be ZERO background checks.
In NewYork City, there is a ban on this kind of firearms too. But it didn't stop men like John Wick from carrying and using all kinds of weaponry.
lastly, those who are targeting the general population will see law abiders as soft touches who can, and WILL be slaughtered at will.