The “AR-style” semi-automatic rifle, recovered at the scene of the attempted assassination of Donald Trump on Saturday, is one of America’s most recognized and contentious weapons. Closely related to the fully automatic M-16 military rifle, the AR-15 has been involved in several high-profile mass shootings in the US, including the 2017 Las Vegas attack that killed 60 people and the 2022 anti-LGBTQ+ shooting in Colorado Springs that left five dead.

Following the attempt on Trump’s life at a rally in Butler, Pennsylvania, the focus has turned to the prevalence of the AR-15 in American society. Sources report that an AR-15 was found near the shooter’s body, a weapon his father had legally purchased.

Gun control advocates argue that the AR-15, named after the ArmaLite company that developed it, is inappropriate for civilian use. “It is a weapon of war suitable only for soldiers in combat,” said Lindsay Nichols, policy director at Giffords Law Center, to NBC last year. “Its capability to kill many people rapidly is why we seek its ban.”

Conversely, many view the rifle as a symbol of the right to bear arms. In February last year, Republican congressman Andrew Clyde, a gun shop owner, distributed AR-15 lapel pins on the House floor, asserting their importance in preserving constitutional liberties.

Journalist Cameron McWhirter, co-author of "American Gun: The True Story of the AR-15," noted the rifle’s significant role in American culture. “This gun has become a symbol,” he told the Guardian in November last year. “Its silhouette is instantly recognizable, whether used to express support for or opposition to gun rights.”

In Pennsylvania, where background checks are mandatory at the point of sale, there are over 2,500 federally licensed firearms dealers. The state generally allows open carry of firearms without a permit, though a permit is needed for carrying in a vehicle or for concealed carry.

In April, the Biden administration moved to close the "gun show loophole," which permits the purchase of guns from unlicensed dealers at shows, online, and in private transactions without background checks.

Developed by the ArmaLite small arms company, the rifle is closely related to the fully automatic military M-16. Its design allows for rapid firing, making it popular among gun enthusiasts but also a frequent choice in mass shootings. The AR-15's ability to inflict mass casualties has led to widespread calls for its regulation or ban, with critics arguing that it is a "weapon of war" unsuitable for civilian use. Despite this, the rifle has become a potent symbol of the Second Amendment rights for many Americans, often sparking intense debate over gun control policies.