Gun control will not work. Gun elimination will.
As an Army vet, I know that a gun placed into a man's hands changes that man. When I left the Army I left guns behind, they represent the worst of humanity.
Guns give carte blanche power to act on emotions, frustrations and fears. Guns provide the power to threaten or to kill, rather than confront with intelligence, empathy or learned self-awareness.
No matter who you are, a loaded gun will change your personality and the situation you find yourself in. Your gun will prevent you from listening and seeing clearly and you will be more apt to act violently and without sufficient forethought.
So-called gun control measures (e.g. profiling gun buyers; limiting sales; outlawing certain gun types; establishing waiting periods; etc.) simply mask the root of gun violence and enables social tolerance. No matter the size or the source of the gun, if it's loaded, the risk of use, abuse and profound consequence are heightened, whether the possessor is socially stable or not.
We all have "acted-out" at some time in our lives. Mass shooters are no different, except for loaded guns. Second amendment arguments be damned. If we refuse to eliminate guns, our schools will become fortresses to guard against them.
Take away all the guns, not just from the criminals, but the cops, the sportsmen, and citizens of all races and creeds. I can only wish!