This article in The Atlantic was written by a radiologist who treated victims of the massacre at Marjory Stoneman Douglas High School in Florida.

In a typical handgun injury that I diagnose almost daily, a bullet leaves a laceration through an organ like the liver. To a radiologist, it appears as a linear, thin, grey bullet track through the organ. There may be bleeding and some bullet fragments.I was looking at a CT scan of one of the victims of the shooting at Marjory Stoneman Douglas High School, who had been brought to the trauma center during my call shift. The organ looked like an overripe melon smashed by a sledgehammer, with extensive bleeding. How could a gunshot wound have caused this much damage?
The reaction in the emergency room was the same. One of the trauma surgeons opened a young victim in the operating room, and found only shreds of the organ that had been hit by a bullet from an AR-15, a semi-automatic rifle which delivers a devastatingly lethal, high-velocity bullet to the victim. There was nothing left to repair, and utterly, devastatingly, nothing that could be done to fix the problem. The injury was fatal.
What to do about semi-automatic weapons like the AR-15, which were designed for the battlefield to kill people? Ban them. Allow only the military to carry them. Keep them away from civilians. Bar their sale at gun shows and online. Arrest anyone who sells them. Confiscate or buy back all those now in existence. Make it a crime for a civilian to own one.Background checks are not enough. A three-day waiting period is meaningless. Nikolas Cruz would have passed the background check and waited three days. Raising the age limit to own a killing machine is not enough. The mass murderer at the Pulse nightclub and the shooter at the Las Vegas festival would have met the age limit and the background check.

Ban them. Limit them for military use only. They are intended for the battlefield, and that is where they belong. Not in schools or nightclubs or churches or anywhere else.

In the future, please refer to the NRA as the Pro-Death Lobby.