Corrections & clarifications: An earlier version of this story incorrectly referenced the legality of machine guns in the United States. Machine guns registered with the ATF before 1986 can still be bought and sold with government approval.
The claim: AR-15 rifles were used in 12 recent mass shootings
Just as it has for other widely publicized incidents in the United States, debate about gun control legislation has followed the news of mass shootings in Atlanta and Boulder, Colorado. The events left 17 Americans dead.
A central question in the debate has been whether to ban assault weapons, defined in the 1994 Federal Assault Weapons Ban as certain semi-automatic firearms and high-capacity ammunition magazines.
Shortly after news broke of the shooting at a grocery store in Boulder, Twitter user Adam C. Best, a progressive activist and founder of the sports site FanSided, posted a tweet that associated the AR-15 rifle with 12 high-profile mass shootings in the last 10 years. The tweet was soon posted to Facebook; one post received over 2,400 reactions and 1,600 shares.
Best's claim is mostly accurate: All but one of the shootings involved the use of at least one AR-15-style assault rifle. However, as we explain below, in several cases shooters had multiple guns — including 23 in the case of the Las Vegas gunman.
USA TODAY reached out to Best for comment. A Facebook page that reposted the tweet, Alexandria Ocasio-Cortez Fans, said it was under the impression that the tweet was true.
What is the AR-15, and how is it different from other popular firearms?
An AR-15 is a type of semiautomatic, or "self-loading," assault rifle.
As defined in U.S. law, the term "semiautomatic," as opposed to "automatic," means the gun's operator must pull the trigger to fire each shot. NPR outlined its most recognizable features: it automatically reloads after each shot and holds around 30 bullets before an operator needs to reload the gun.
Dubbed "America's Rifle" by the NRA, the AR-15 is popular for its easy-to-modify design and lack of recoil or "blowback" after firing, which preserves the operator's aim and makes the shot more precise, as The Washington Post detailed in a Q & A on the firearm.
While the AR-15 is not a machine gun, a user can modify the AR-15 to approximate the function of an automatic gun by attaching a device called a "bump stock", as was the case in the Las Vegas shooting.
Soon after the mass shooting at Marjory Stoneman Douglas High School in Parkland, Fla. in February 2018, the Trump administration took action against bump stocks. The ATF issued a rule that changed the definition of "machine gun" to include bump stock devices, therefore rendering them illegal to possess. However, the U.S. Court of Appeals for the Sixth Circuit put a hold on the ban in March because it could be unconstitutional, in a lawsuit filed by Gun Owners of America, Inc., Bloomberg Law reported. The future of the ban remains uncertain.
(Weapons in the machine gun category cannot be manufactured for civilian use in the United States, though a 1986 law still allows fully automatic weapons registered with the ATF before 1986 to be bought and sold, after paying a fee and submitting an application and other paperwork.)
The Washington Post and NPR trace the history of the modern AR-15 back to the 1950s, when its original manufacturer ArmaLite (now Colt) created the M-16 machine gun. The M-16 became standard issue for American troops fighting in the Vietnam War.
After the war, the company named a semiautomatic version after itself (AR stands for "ArmaLite Rifle," not "assault rifle") and marketed it to the public. Because the original patent has expired, the AR-15 is now the generic name for many variants created by a variety of firearms makers.
USA TODAY researched each shooting that Best mentioned and found that in 11 out of 12 of the incidents listed, AR-15-style rifles were used. The sole exception is the Orlando Pulse Nightclub shooting, in which the shooter used an assault rifle that is not considered an AR-15 variant.
In the list below, we detail the weapon or weapons used in each shooting, in addition to the number of victims and their dates. Click on the headers for more information about the incidents from USA TODAY.
Date: March 10
Lives lost: 10
Weapon used: Ruger AR-556 pistol
The Washington Post reported that the prime suspect in the shooting, Ahmad Al Aliwi Alissa, purchased a Ruger AR-556 pistol on March 16, just four days after the state of Colorado's two-year assault weapons ban was blocked in court.
Date: June 12, 2016
Lives lost: 49
Weapon used: Sig Sauer MCX
The Sig Sauer MCX is marketed as a "modern sporting rifle" and is very similar to the AR-15 in form and function. However, as explained in a Slate analysis, it is not an AR-15 variant because it uses a gas piston system to propel bullets from within the gun instead of a direct impingement system. It is also more modular, so parts can be switched out and customized more easily, says Tactical Life magazine.
Date: Feb. 14, 2018
Lives lost: 17
Date: Oct. 1, 2017
Lives lost: 58
Several of the AR-15 variants used in the Las Vegas shooting had a bump stock attached, which allows guns to fire roughly as rapidly as a machine gun.
Date: July 20, 2012
Lives lost: 12
Date: April 22, 2018
Lives lost: 4
Date: Dec. 2, 2015
Lives lost: 14
Date: Aug. 31, 2019
Lives lost: 7
Date: Apr. 27, 2019
Lives lost: 1
Date: Oct. 27, 2018
Lives lost: 11
Our rating: Missing context
We rate this claim MISSING CONTEXT, because without additional information it could be misleading. All but one of the shootings involved the use of an AR-15-style assault rifle, and the shooting that did not use an AR-15 used a very similar assault rifle. However, the lack of context could lead a reader to believe that the shooters in all incidents listed only used an AR-15, when in several cases they had multiple guns — including 23 in the case of the Las Vegas gunman.
Our fact-check sources:
Adam Best (@adamcbest), March 22, tweet
Axios, Sep. 7, 2019, What the deadliest mass shootings have in common
Bloomberg Law, March 25, Federal Bump Stock Ban Blocked by Divided Appeals Court
Bureau of Alcohol, Tobacco and Firearms, last updated Feb. 21, 2019, Bump Stocks
CBS News, March 26, Gun used in Boulder mass shooting was bought legally, police chief says
GunDigest, June 18, 2014, 6 Facts About AR-15 Direct Impingement Vs. Gas Piston
The New York Times Interactive, last updated Feb. 16, 2018, How They Got Their Guns
The New York Times, July 23, 2012, Aurora Gunman’s Arsenal: Shotgun, Semiautomatic Rifle and, at the End, a Pistol
NBC News, July 12, 2016, AR-15 Style Rifle Used in Orlando Massacre Has Bloody Pedigree
NPR, Feb. 28, 2018, A Brief History of the AR-15
Slate, June 14, 2016, Omar Mateen Had a "Modern Sporting Rifle"
The Tennessean, April 22, 2018, Waffle House shooting: Police confirm AR-15 used in attack at Antioch diner
U.S. Attorney’s Office for the Northern District of Texas, Jan. 7, Man Who Sold Midland/Odessa Shooter AR-15 Used in Massacre Sentenced for Unlicensed Firearms Dealing
U.S. Attorney’s Office for the Western District of Penn., Jan. 29, 2019, Additional Charges Filed in Tree of Life Synagogue Shooting
United States District Court for the Southern District of California, May 9, 2019, Final Complaint, United States of America v. John Timothy Earnest
USA TODAY, Nov. 12, 2019, Supreme Court refuses to block lawsuit against gun manufacturer brought by Sandy Hook families
USA TODAY, Oct. 3, 2017, What guns were used in the Las Vegas shooting?
Washington Post, Feb. 15, 2018, It’s time to bring back the assault weapons ban, gun violence experts say
Washington Post, Feb. 16, 2018, Basic Questions about the AR-15
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This article originally appeared on USA TODAY: Fact check: Post missing context about AR-15 rifles and mass shootings