WASHINGTON — Texas-based bump stock maker Slide Fire will stop sales on May 20, the company announced on its website Tuesday.

Slide Fire is the country's largest manufacturer of the device, which allows a semi-automatic rifle to fire at nearly automatic rates. Bump stocks were found on multiple guns in the hotel room used as a sniper’s perch during a Las Vegas rampage on Oct. 1 that left nearly 60 people dead.

Some lawmakers demanded a federal ban. President Donald Trump last month ordered the Justice Department and Department of Alcohol, Tobacco, Firearms and Explosives to revisit an Obama-era ATF decision classifying the device as an accessory the agency had no authority to regulate.

ATF estimates that up to a half-million devices are already in the hands of gun owners. The agency issued a proposal to ban bump stocks on March 29, setting off a 90-day comment period that ends June 27.

If the ban goes into effect after that, owners would be required to destroy the devices, which cost $180 to $400, or turn them into authorities, and Slide Fire would have to destroy any inventory.

The privately owned company, based in the tiny town of Moran, near Abilene, suspended orders after the Las Vegas shooting, but resumed sales weeks later.

"On Sunday, May 20, 2018 at midnight CST, Slide Fire will cease taking orders for its products and shut down its website," read the notice on the company's site. "Orders placed prior to May 20th, 2018 will all be processed and shipped."

CNN Money first reported the development.

Relatively few gun owners had heard of bump stocks before Stephen Paddock shot up an outdoor country music concert in Las Vegas.

Since then, gun stores around the country have reported a spike in sales, as gun owners sought to obtain one of the devices in anticipation of a possible ban.

Some have vowed to keep theirs even if the ban goes into effect.

1 / 4A man lays on top of a woman as others flee the Route 91 Harvest country music festival grounds during a shooting rampage in Las Vegas on Oct. 1, 2017. (David Becker for Getty Images / AP) 2 / 4A broken window where a gunman opened fire from an upper story of Mandalay Bay resort on a country music festival across the street on the Las Vegas Strip, leaving 58 dead and more than 500 injured, shown on October 2, 2017, in Las Vegas.(Marcus Yam / Los Angeles Times) 3 / 4Michael Cargill, Central Texas Gun Works owner, poses with an AR-15 with a bump stock attached in his store in Austin on October 19, 2017. In the aftermath of the Las Vegas concert massacre, some lawmakers have called for a ban on "bump stocks" and even the National Rifle Association has urged a federal agency to reassess whether the device should be regulated. But gun owners and others question how to enforce a ban on the accessory that allows a rifle to fire at nearly automatic rates.(Vernon Bryant / Staff Photographer) 4 / 4Notice posted on Slide Fire's website on April 17, 2018, indicating the company will stop taking orders on May 20th.

Slide Fire has encouraged opposition to the ban. Earlier this month, the company posted a video on Facebook by "The Gun Collective" that railed against the impending "overreach" by the federal government.

“ATF is about to retroactively make you a criminal if you own a bump stock,” the video says. “This is obviously a huge problem.”

But Slide Fire's owner, Jeremiah Cottle, has stayed out of the debate and away from the press. In October, Cottle told The Dallas Morning News he was heartened by the support he's received from Moran residents.

If his business had to close, Cottle said, "it would hurt the whole town, the school. We pay a very large amount of property taxes. I'm one of the largest businesses in Shackelford County."

Moran had a population of 270 in the last census. At its peak, Slide Fire employed 27 people — equal to one-tenth of the town's population.

ATF estimates that it would cost $1.8 million to destroy all existing bump stocks. Its proposal does not include compensation for owners or manufacturers.

After the commenting period ends in late June, the agency will review comments. A final rule would then go to the Office of Information and Regulatory Affairs for approval.

ATF's first draft of a proposed ban drew 100,000 comments, about 85 percent of them opposed to the idea, according to an analysis from The Trace, a media organization that reports on gun-related news. More than 15,000 people have commented so far on the agency's latest draft.

ATF has reported that 2,281 retailers and two manufacturers would be impacted. The proposal is expected to cost the industry, public and government more than $200 million over 10 years for lost production and sales. But, the agency says, destroying contraband devices is fairly easy.

“Since the majority of bump-stock-type devices are made of plastic material, individuals wishing to destroy the devices themselves could simply use a hammer to break apart the devices and throw the pieces away,” ATF’s proposal reads.