Mass shootings involving guns have become a fact of American culture. While mass murders happened throughout recorded history, changing civilian gun technology has made the murders more deadly.

In 1966 the deadliest mass murder in U.S. history up to that point took place at the University of Texas at Austin. The “Texas Tower Sniper”* killed 16 people and wounded 31 over 96 minutes, using a bolt action rifle and semiautomatic weapons. His weapons allowed him to achieve a casualty rate of one every two minutes.
The current deadliest mass murder in the United States took place in Las Vegas, Nevada in 2017. Firing from a hotel into a country music festival, a shooter killed 58 people and wounded 546 over 10 minutes. By using assault rifles converted into automatic weapons, he achieved a casualty rate of one per second.
However, most gun deaths are not mass shootings. For example, in 2015 gun suicides killed 22,000 Americans, homicides killed 13,000 people, and mass shootings killed 46.