I think the answer is closer to treating them similarly to automatic weapons. They are not banned completely, they are simply regulated with strict access controls.
We don’t have school shootings with automatic weapons, do we? (Note the Vegas bump stock skirted this ban specifically)
Typically 2 or more of: pistol grip, collapsible/folding stock, barrel over x length, semiautomatic firing mechanics, magazines located outside the grip.
See the former Federal Assault Weapons Ban in place from 1994-2004. https://en.m.wikipedia.org/wiki/Federal_Assault_Weapons_Ban