The Supreme Court has struck down the federal ban on bump stocks.

In its ruling, the majority said the stocks did not qualify as machine guns under a 1986 law that banned civilians from owning the weapons. The Trump administration interpreted a law banning bumper shots in 2018 after a gunman used the device to open fire at a Las Vegas music festival, ultimately killing 60 people in the deadliest mass shooting in U.S. history.

In dissenting, Justice Sonia Sotomayor said the majority opinion would have “deadly consequences,” adding that the court was “hampering the government’s efforts to keep machine guns from gunmen like the Las Vegas shooter.”

Michael Cargill, a U.S. Army veteran and Austin gun store owner, challenged the ban after he was forced to surrender two of his stash. He argued that the Bureau of Alcohol, Tobacco and Firearms exceeded the limit when it reclassified bump stocks as machine guns in 2017, following public calls to ban the devices.

The agency previously ruled that the stocks were legal to possess, ruling they were not machine guns. According to ATF data, between 2008 and 2017, Americans bought about 520,000 of the supplies, provided they were legal.

Stocks are a piece of molded plastic or metal that replaces the rifle’s stock and the grip closest to the trigger. This element allows the gun parts to move freely back and forth. The recoil after the shot causes the gun to “fall” between the shooter’s shoulder and the trigger finger, causing shots to be fired in quick succession.

Stock-equipped rifles can fire approximately 400 to 800 rounds per minute, a rate similar to that of an automatic weapon.

The case of the so-called Garland v. Cargill, included whether the stocks met the definition of a machine gun under the 1986 law. The federal appeals court was sharply divided on the issue in five previous rulings on the legality of the ban before the Supreme Court took up Cargill’s lawsuit.

The Cargill case did not directly involve the Second Amendment, but rather was a test of a federal agency’s reach to make and interpret regulations – a central issue of the Supreme Court’s current term. Other cases involve the Securities and Exchange Commission, the Consumer Financial Protection Bureau and legal precedent that states courts should defer agency interpretations of ambiguous statutes if they are warranted.

The 1986 Act defines a machine gun as “any weapon that fires, is designed to fire, or can be readily restored to firing by automatically firing more than one shot, without manual reloading, by the operation of a single trigger function.”

The Biden administration defended the Trump administration’s interpretation that bump stocks are machine guns, arguing that the devices allow semi-automatic rifles to fire automatically with a single press of the trigger. However, Cargill lawyers disputed this characterization, arguing that the stock is activated by repeatedly pressing the trigger.

Most of the oral arguments in the February case focused on how emergency operations would work. At one point, Judge Elena Kagan and Cargill attorney Jonathan Mitchell took turns using their hands to demonstrate what it looked like to shoot a gun equipped with one of the devices.

Buffer stocks were invented in the early 21st century, but the question of their legality has changed frequently. In 2003, the ATF concluded that the early version was not a machine gun, but later changed its position to ban a version of the device equipped with an internal spring to facilitate firing. In 2008, the agency changed course again, approving a springless model.

During oral argument, Justices Neil M. Gorsuch and Brett M. Kavanaugh questioned the government’s evolving interpretation of whether bump stocks are machine guns. Gorsuch added that he understands why the government would want to ban the devices, but said Congress must do so clearly.

Liberal Justices Ketanji Brown Jackson and Kagan found that bump stocks were the type of weapon that Congress intended to ban under the 1986 Machine Gun Act.

Cargill filed a lawsuit challenging the ban in 2019, the same day it surrendered its shares to the ATF.

A U.S. district court dismissed Cargill’s claims, and a three-judge panel of the conservative Fifth Circuit Court of Appeals upheld the ruling. The full Fifth Circuit Court of Appeals then heard the case and reversed the decision. The Biden administration challenged this decision to the Supreme Court.

Meanwhile, the Supreme Court struck down a New York law that required a permit to carry a gun in public starting in 2022. Writing for the majority, Justice Clarence Thomas established an important new test that gun restrictions must be consistent with the country’s history of gun laws flammable.

Since then, gun advocates have challenged dozens of gun laws in court, arguing that they have no parallel in American history. These efforts have resulted in messy and unstable gun laws.

Some courts have upheld restrictions, while others have struck down bans on “ghost guns,” high-capacity magazines, restrictions on firearm purchases by young adults and other laws.

The legal battles unfolded at a moment of national concern over gun violence and fierce debates over gun control.

According to the Washington Post, there were 39 mass shootings in the United States last year, the highest number since 2006. According to another Post database, there was a record 46 school shootings in 2022, the highest number since at least 1999. A spike in homicides during the pandemic has also raised concerns, although that trend has eased in most places.