In Fight Over Bump Stock Ban, Lawyers Take Aim at Administrative State

A simple device that speeds up a semiautomatic weapon’s rate of fire is at the center of a case that could cast a shadow over a government agency’s ability to regulate firearms.

For Michael Cargill, a fierce defender of gun rights who sells firearms in Austin, the accessory, a bump stock, was until 2017 a niche item on the shelves of his store, Central Texas Gun Works. It mainly appealed to people who were injured or disabled, like veterans who needed support firing a gun or by “people who just wanted to have fun,” he said.

But that year, a high-stakes gambler stationed on the 32nd floor of a Las Vegas hotel opened fire on a country music festival, killing 60 people and injuring hundreds. In his arsenal were a dozen AR-15-style rifles outfitted with the device.

Government officials swiftly called for a ban, eliciting alarm among gun store owners like Mr. Cargill, 54, a gregarious Army veteran who said that the mugging and assault of his grandmother had shaped his views on gun control.

“I was one of the only people who said, hold on, wait a minute,” said Mr. Cargill, who has challenged the ban and is represented by the New Civil Liberties Alliance, a legal advocacy group that primarily challenges what it views as unlawful uses of administrative power. “This is insane that anyone would go along with this. We need to stop this now.”

On Wednesday, the Supreme Court will consider whether the Trump administration acted lawfully in enacting a ban that makes it illegal to buy or possess the part. It is not a case that turns on the Second Amendment. Rather, it is one of a number of challenges aimed at limiting the reach of administrative agencies — in this instance, the Bureau of Alcohol, Tobacco, Firearms and Explosives.