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H.R. 3999 (115th): To amend title 18, United States Code, to prohibit the manufacture, possession, or transfer of any part or combination of parts that is designed and functions to increase the rate of fire of a semiautomatic rifle but does not convert the semiautomatic rifle into a machinegun, and for other purposes.

Semi-automatic weapons are legal in America. Automatic weapons are illegal. But what about a device that converts a semi-automatic weapon into an automatic-like firearm?

Such a device, called a bump stock, was used in the Las Vegas massacre last week. The Automatic Gun Fire Prevention Act, labelled S. 1916 and H.R. 3999, was introduced by Sen. Dianne Feinstein (D-CA) and Rep. Carlos Curbelo (R-FL26) within days and would ban bump stock devices.

Context

Last week’s massacre at a country music concert in Las Vegas was the deadliest in U.S. history, killing at least 59 people.

The perpetrator used bump stocks, an add-on to a gun which “bumps” the trigger to drastically increase the number of rounds fired. With bump stocks, a gun can shoot as many as 800 rounds per minute, equivalent to about 13 shots per second. As audio from the event demonstrated, a semi-automatic with a bump stock is not readily distinguishable from a fully automatic firearm.

Automatic weapons have been banned in the U.S. since 1986, yet a device that effectively turned a legal weapon into an illegal one was permitted nonetheless. The devices are obscure enough that many gun-owning NRA-endorsed congressional Republicans didn’t know what they were.

What supporters say

Speaker Paul Ryan (R-WI1), an ardent conservative, has come out in favor of banning bump stocks while other supporters argue the bill fixes a loophole which allows the circumventing of an existing gun control law that’s been on the books for decades — an argument that could in theory appeal to conservatives who often argue “enforce the existing law” on such other issues as immigration.

“Automatic weapons have been illegal for more than 30 years, but there’s a loophole in the law that can be exploited to allow killers to fire at rates of between 400 and 800 rounds per minute,” Senate lead sponsor Feinstein said in a press release.

“The only reason to fire so many rounds so fast is to kill large numbers of people,” Feinstein continued. “No one should be able to easily and cheaply modify legal weapons into what are essentially machine guns.”

And while the National Rifle Association had initially said it was open to the regulation of bump stocks, it opposes this bill (more on that below)

What opponents say

Some conservatives are opposed to any form of gun control on principle, declaring the Second Amendment inviolable.

One Republican opponent of the bill in particular has surprised many: Sen. Pat Toomey (R-PA), among the only Senate Republicans who voted for expanded background checks and a few other gun control measures in the wake of the 2012 Newtown massacre.

“I am very skeptical about legislation that attempts to ban features and particular guns,” Toomey said in explaining his reasoning, implying that he’s more amenable to reforms like background checks which affect every gun owner rather than targeting a specific subset.

Opponents also note that not a single one of the 91 U.S. mass shootings since 1982 used a fully automatic weapon.

The NRA

Further, the NRA, which was the preeminent actor blocking gun control legislation including background checks in the wake of the 2012 Newtown and 2016 Orlando massacres, has expressed openness to regulating — as opposed to banning — bump stocks: “Despite the fact that the Obama administration approved the sale of bump fire stocks on at least two occasions, the [NRA] is calling on the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE) to immediately review whether these devices comply with federal law,” the NRA’s Wayne LaPierre and Chris Cox said in a joint press release.

“The NRA believes that devices designed to allow semi-automatic rifles to function like fully-automatic rifles should be subject to additional regulations,” the press release continued, marking a sharp turn (at least in recent years) from their libertarian stance towards firearms.

But now that the NRA is officially opposing Feinstein’s bill, this could further lessen its chances of passing.

President Trump campaigned against gun control, but has yet to make any public indication of his stance on bump stocks. However, a congressman who flew on Air Force One with Trump on Wednesday told the Associated Press that an onboard discussion indicated Trump was open to regulation or banning. That notwithstanding,, President Trump has not yet come out either way for or against the bill. If he ultimately announces his opposition, that alone may sink the legislation.

Odds of passage

Almost every Democrat and even a solid number of Republicans — including some of the highest-ranking Republicans — seem to be on board.

Then again, in today’s Washington, even such overwhelming support does not necessarily guarantee success. One ominous sign could be that although some Republicans are expressing tentative approval in statements or interviews, the bill has 38 Senate cosponsors — none of them Republicans.

10/13/2017: This article has been revised and rearranged to reflect the NRA’s recent announcement it will oppose the bill and to include a link to Rep. Curbelo’s bill on the same topic.

Last updated Oct 13, 2017. View all GovTrack summaries.

The summary below was written by the Congressional Research Service, which is a nonpartisan division of the Library of Congress, and was published on Oct 10, 2017.


This bill amends the federal criminal code to prohibit certain conduct with respect to any part or combination of parts that is designed and functions to increase the rate of fire of a semiautomatic rifle but does not convert the semiautomatic rifle into a machine gun.

Specifically, it makes it a crime to manufacture, possess, or transfer such device: (1) in or affecting interstate or foreign commerce, or (2) that has been shipped or transported in interstate or foreign commerce.

An individual who knowingly violates the prohibition is subject to criminal penalties—a fine, a prison term of up to five years, or both.

Additionally, the U.S. Sentencing Commission must review and amend the sentencing guidelines and policy statements to provide an enhanced penalty if the device has been: (1) used, carried, or possessed during or in relation to a crime of violence or drug trafficking crime; or (2) unlawfully smuggled into or from the United States.