AR-15 Rifles Were Used in 26 Percent of the Last 80 Mass Shootings in America

Of the last 80 mass shootings in the United States, more than a quarter, including Monday's shooting in Boulder, Colorado, involved the use of AR-15 rifles.

A Newsweek analysis found that the semi-automatic rifle was used in 21 mass shootings over the past decade.

Among those incidents are some of the deadliest mass shootings in the nation's history, including the Las Vegas shooting, which left 59 people dead; the Orlando, Florida, nightclub shooting, which killed 50; and the Sandy Hook Elementary School shooting in Connecticut, which killed 28.

On Monday afternoon, a gunman opened fire at a grocery store in Boulder, killing 10 people, including 51-year-old veteran police officer Eric Talley, who was the first to report to the scene.

A senior law enforcement officer with the Boulder police told CNN that the weapon used was an AR-15-style rifle, the same type of weapon used in the 2018 Parkland, Florida, school shooting and the Colorado theater shooting in 2012.

While there's no legal definition of a mass shooting, the federal government has said that the killing of at least four victims constitutes a mass murder.

AR-15-style assault rifles have been a common trend in some of the deadliest mass shootings. These weapons possess an enormous amount of killing power because they can inflict what one of their designers called "maximum wound effect." These weapons are generally able to fire far more bullets at a faster rate than manual-action hunting rifles.

AR 15
A customer handles an AR-15 at Jimmy's Sport Shop in Mineola, New York, on September 25, 2020. AR-15 rifles were used in 26 percent of the last 80 mass shootings in the United States. Timothy A. Clary/AFP

Assault weapons have become the target of many gun reform organizations pushing for states to ban these types of guns. Currently, only seven states and the District of Columbia prohibit assault weapons.

A 2018 study found that fatalities were lower when a federal ban on assault weapons was in effect between 1994 and 2004. State assault weapons bans have also been associated with a lower likelihood of an active shooter event. Colorado does not have an assault weapons ban.

However, gun rights advocates have defended the ownership of these weapons, arguing that they are among those protected by the Second Amendment.

Of the last 80 mass shootings in the country, an AR-15 gun was used in:


  • The Boulder shooting this week
  • The 2019 Jersey City, New Jersey shooting
  • The Midland-Odessa interstate shooting in Texas in 2019
  • The 2019 Dayton shooting in Ohio
  • The Tree of Life synagogue shooting in Pittsburgh in 2018
  • The Waffle House shooting in Nashville in 2018
  • The 2018 shooting at Marjory Stoneman Douglas High School
  • The 2018 Melcroft, Pennsylvania, shooting
  • The shootings at Rancho Tehama Reserve in California in 2017
  • The Sutherland Springs, Texas, church shooting in 2017
  • The 2017 Las Vegas shooting
  • The 2017 Plano, Texas, shooting
  • The 2017 Lincoln County, Mississippi, shootings
  • The Orlando nightclub shooting in 2016
  • The 2015 San Bernardino, California, attack
  • The 2015 Colorado Springs, Colorado, shooting
  • The 2013 Santa Monica, California, shooting
  • The 2013 homicides in South Valley, New Mexico
  • The 2012 Webster, New York, shooting
  • The Sandy Hook Elementary shooting in Newtown, Connecticut, in 2012
Mass shootings in U.S. - Statista