At the risk of repeating myself at promoting technological solutions. I keep seeing the "people being killed by/in cars" argument and the "why don't we ban cars?" statement.
Yes, people die in cars and from being hit by cars. We didn't ban cars. We didn't even ban the fastest cars. We did, however, introduce speed limits on roads, seat belts, air bags, anti lock brakes, crumple zones, collision detection systems, headlamps, windscreen wipers, head cushions, tyre technology for bad weather etc etc all in order to make cars safer for the owners and for other road users and pedestrians.
So again, how about some technologies to help prevent nutters from gunning down innocent people as opposed to stopping people from owning guns.