Criminals will get the guns they want. No background check laws have ever prevented a criminal from eventually getting a gun.
The problem is what happens if an assault weapons ban is passed? Are the people who responded in this thread going to comply with the law and support enforcement of that law?
The first US gun laws were used to disarm law abiding people who suddenly became a criminal and hand their guns over to the authorities or the Klan would come knocking.
If a person is too dangerous to own a gun than they are too dangerous to be free out in society.