America's gun problem, explained
vox.com
vox.com
The Boston marathon bombers showed you don't need guns. As did the Oklahoma one. There are designs of all kinds of deadly stuff shared in the darker parts of the Internet, some of them perfected from decades of war.
If someones goes crazy enough to want to murder people he doesn't know - will the fact that he may have to buy his tools for the deed on the black market or jury rig them somehow deter him?
Gun control won't be the silver bullet that will stop the mass shootings. It may transform them from shootings to bombings or car rammings. Or worse stuff.
I'm not sure whether we should praise Wikipedia for compiling such lists! but https://en.m.wikipedia.org/wiki/List_of_rampage_killers disagrees with that. Also, the claim isn't that private gun ownership causes all mass shootings, it is that it explains a large part of the difference in occurrence rate between the US and other countries.
Compare levels of gun violence in two border cities with very similar demographics: El Paso, Texas and Juarez, Chihuahua State.
One one side of the border, gun ownership and carry rights are quite strong. On the other, handguns are essentially banned.
Which do you think has more violent crime?