The only common element of all mass killings in this country is a gun.
Some studies suggest that there are more guns in the country than people, and according to available data, most are the possession of 5 million people.
The US Department of Justice defines a mass killing as one in which there are four or more victims. The most common of these usually don’t get much press since they are domestic violence instances. These typically involve a man killing his female partner and their/her children before shooting himself. In almost all cases, the murderer owned the gun legally, usually purchased for self-protection.
The solution to reducing gun violence in this country is to reduce the number of guns here. Congress could, if it had the courage to do so, create a program to buy back all guns except those appropriate for hunting.
No one uses a .50-caliber snipe rifle or a semiautomatic assault rifle to hunt game. These were developed for the military and should remain limited to use by the military. The same is true of semiautomatic handguns. Law enforcement demanded larger and more lethal weapons to counter the massive influx of illegal guns in the streets. Reduce the total number of guns available and this issue becomes moot.
Along with buyback, Congress can ban the importation, manufacture, distribution and sale of guns not typically used for hunting. No one’s constitutionally protected right would be violated by these actions.