The Justice Department has taken the first step in banning the sale, manufacture or possession of bump stocks through new regulation, as Congress stalls in drafting a legislative prohibition.
"The Department of Justice has submitted to the Office of Management and Budget a notice of a proposed regulation to clarify that the National Firearms and Gun Control Act defines 'machinegun' to include bump stock type devices," Attorney General Jeff Sessions said in a statement issued Saturday.
Bump stocks are devices used to accelerate a gun's shooting rate so it fires like an automatic weapon.
As NPR's Jessica Taylor reported, President Trump called on the Justice Department to change its regulations and formally ban the devices in February, following the deadly high school shooting in Parkland, Fla.
The alleged shooter in the school massacre that killed 17 people did not use bump stocks, but the gunman who killed 58 concertgoers and injured more than 500 others in October in Las Vegas did.
The Bureau of Alcohol, Tobacco, Firearms and Explosives recently closed the public comment period for its review of bump stock regulation. But in a 2010 assessment, the ATF concluded that the devices were not regulated under existing gun laws. And it ruled that only Congress can act to ban them.
That is a view shared by gun safety supporters, including Sen. Dianne Feinstein, D-Calif., who pushed for a legislative ban last fall.
"If ATF tries to ban these devices after admitting repeatedly that it lacks the authority to do so, that process could be tied up in court for years, and that would mean bump stocks would continue to be sold," Feinstein said in a February statement.
"Legislation is the only answer," she added.
The National Rifle Association is against a ban, but the organization says "devices designed to allow semi-automatic rifles to function like fully-automatic rifles should be subject to additional regulations."
The NRA did not immediately respond to requests for comment by NPR. However, The Associated Press reported that the powerful lobby group filed a lawsuit against the state of Florida on Friday after the governor signed a package new gun restrictions, including a ban on bump stocks.