The Bureau of Alcohol, Tobacco, Firearms and Explosives took what could be the first step toward reclassifying bump stocks on Thursday, posting a document that asks manufacturers and retailers how they would be affected if the devices were regulated as machine guns.  

The draft document, which is available on the Federal Register, said the Department of Justice intends to clarify whether bump stocks should be classified as machine guns under federal law. Before it does, the ATF will seek detailed information from bump stock manufacturers, sellers, and owners about their businesses and the device’s intended use, the document shows.

“If ATF classified bump stock devices as ‘machineguns’ … what other economic impact would you expect (e.g., storage, unsellable inventory)?” the document asks.

The document will remain “unpublished” on the Federal Register until December 26. When it is officially published, there will be a 30-day window for the public to submit comments.

Calls to the ATF seeking comment on the document were not returned Thursday.

Bump stocks are devices that are designed to make a semiautomatic weapon mimic a machine gun by harnessing its recoil. They are not currently regulated under federal law, and can be purchased in most states without a background check. 

The device’s legality has been under scrutiny since October, when authorities found more than a dozen bump stocks attached to rifles recovered from the hotel room of the man who killed 58 people at a Las Vegas music festival. In the wake of the shooting, some experts and lawmakers called on Congress to ban the devices.

Senator Dianne Feinstein of California sponsored a bill that would place an outright prohibition on the sale or possession of the devices. But the bill stalled after the National Rifle Association suggested that the ATF could “do its job” and regulate bump stocks without legislative action. The Justice Department then announced that the ATF would start an administrative review of the ruling.

The call for public comment posted Thursday would be a first step in that review.

Richard Vasquez, who oversaw the ATF’s original ruling on bump stocks, told The Trace in October that, under existing law, the agency could not have banned bump stocks. He said a bump stock does not transform a rifle into a machine gun because the trigger of a rifle equipped with the device has to be engaged every time the weapon is fired.

Bradley Buckles, who served as the ATF director from 1999 to 2004, said Thursday he cannot see how the agency could legally ban bump stocks. He said it is more likely an attempt to distract Congress from passing legislation until public outrage over the issue has passed.

“The Justice Department’s tepid move toward new regulations does not appear to be a good faith effort to quickly address a very real public safety issue,” Buckles told The Trace in an email. “To the contrary it appears more likely to be little more than a delaying tactic designed to provide the Congress a reason not to address the issue.”

The document also shed light on the fact that, because bump stocks are not regulated, the ATF does not know how many companies manufacture them, or how many of the devices exist.

If the ATF were to regulate bump stocks in the future, it would likely mean that anyone who currently owns one would either have to register it, or get rid of it.