The United States Supreme Court, which expanded gun rights in a landmark decision in June, declined to hear a challenge to a federal ban on “bump stocks,” which allow semi-automatic weapons to fire like machine guns – a firearms control measure prompted by a mass shooting in Las Vegas in 2017.

The justices denied appeals of lower court rulings upholding the ban as a reasonable interpretation of a federal law prohibiting machine gun possession filed by a Utah gun lobbyist named Clark Aposhian and firearms rights groups.

The issue was former President Donald Trump’s administration’s decision to reclassify bump stocks as prohibited machine guns under US law in a policy that took effect in 2019.

Bump stocks use the recoil of a gun to bump the trigger, allowing a semiautomatic weapon to fire hundreds of rounds per minute and shoot like a machine gun. Soon after a gunman used semiautomatic weapons outfitted with bump stock devices to kill 58 people at a country music festival in Las Vegas, Trump promised to ban them.

Following the massacre, the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), a United States Justice Department agency, reversed a previous conclusion and classified bump stocks as illegal under the 1934 National Firearms Act, which was enacted in response to gangster violence of the time. Trump also directed the Justice Department to issue a rule prohibiting the use of bump stocks.

In a 6-3 decision in June, the court declared for the first time that the U.S. Constitution protects an individual’s right to carry a handgun in public for self-defense. In a country divided over how to address firearms violence, the decision gave gun rights advocates a victory.

The ruling, which overturned New York state limits on carrying concealed handguns outside the home, was overturned by the court’s three liberal justices.

The bump stock ban, imposed without congressional action, required owners to surrender or destroy the attachments, with those caught in possession facing up to ten years in prison.

Gun control legislation is rarely enacted at the federal level. President Joe Biden signed the first major federal gun reform legislation in three decades into law in June, just two days after the Supreme Court’s decision in the New York case. That law was intended to help prevent dangerous people from obtaining firearms and to increase investments in the United States’ mental health system.

According to the Utah Shooting Sports Council’s website, Aposhian is the chairman. The organization works to persuade the Utah State Legislature to “defeat gun control and pass pro-gun legislation.”

In 2019, Aposhian filed a lawsuit to overturn the ban, questioning the ATF’s authority in reclassifying bump stocks as prohibited machine guns. Aposhian surrendered his bump stock pending the outcome of the litigation after a federal judge refused to grant him an injunction early in the case.

The ban was upheld in 2020 by the Denver-based 10th U.S. Circuit Court of Appeals, which refused to second-guess the ATF’s reinterpretation of the term “machine gun” under federal law.

Separately, gun rights advocates, including Gun Owners of America and three of its individual members, filed a federal lawsuit in Michigan to prevent the bump stock ban from going into effect. In 2021, the ban was upheld by the 6th U.S. Circuit Court of Appeals in Cincinnati.

The Supreme Court appeals contend that lower courts improperly deferred to the ATF’s actions. In 2019, the Supreme Court declined to prevent the ban from going into effect.

The National Rifle Association, a gun rights organization closely aligned with Republicans, filed a friend-of-the-court brief in support of Aposhian with the Supreme Court. Trump’s Republican colleagues support a broad interpretation of the Second Amendment’s promise to keep and bear arms.