Why aren’t bump fire stocks regulated like machine guns?

The bump stock attached to an AR rifle. (Photo: Eve Flanigan/Guns.com)

The bump stock attached to an AR rifle. (Photo: Eve Flanigan/Guns.com)

Details about bump stocks and machine guns have been making headlines across the country after the Las Vegas shooting, but what are those laws and why don’t they cover bump stocks?

The short answer to the question is bump stock do not change the internal components of a firearm to make the gun perform like a machine gun. But the long answer is a bit more detailed and could fill an entire book.

The two primary laws that permit the federal government to regulate guns include the National Firearms Act and the Gun Control Act. The former was designed to create a tax on uncommon weapons while the latter permits the feds to regulate firearms in interstate commerce. The Bureau of Alcohol, Tobacco, Firearms and Explosives enforces both of them.

The NFA imposes a $200 tax on the manufacture, sale and transfer of machine guns as well as silencers, short barreled rifles or shotguns, devices deemed Any Other Weapon, and destructive devices. In addition to the tax, they require a rigmarole of paperwork and checks.

Detailing the history behind the law, the American Bar Association said Congress passed the legislation in response to Prohibition-era violence. “The act had the added incentive to curtail the use of weapons popular in gangland-style shootings, such as the St. Valentine’s Day Massacre in Chicago in 1929 when four of Al Capone’s henchmen, dressed as policemen, murdered seven members of rival Bugs Moran’s gang,” the ABA said.

Congressional transcripts about the law from 1934 show that lawmakers wanted to give law enforcement stronger tools so they could arrest criminals who would flee a state after using those aforementioned devices to commit crimes. The price at the time, $200, was high enough to make it expensive and difficult to obtain the items. If adjusted for inflation, the tax would cost more than $3,500 today.

Congress updated federal gun laws in 1968 — after the assassinations of President John F. Kennedy, Martin Luther King, Jr. and Sen. Robert F. Kennedy — with the GCA, which banned mail order sales of firearms and created a list of prohibited buyers like most felons, drug users and the mentally incompetent. The law also expanded the definition of firearm to mean “destructive devices” as well as the definition of machine gun, the ABA said.

Then, in 1986, Congress added the Hughes Amendment, which limited the transfer or possession of machine guns except for those manufactured before May 19, 1986, the ABA said. According to the National Rifle Association, the Hughes Amendment aimed to limit the number of machine guns commercially available to 150,000, but an exact number is unclear.

According to the ATF, NFA defines a machine gun as any weapon that shoots or is designed to shoot automatically with a single pull of the trigger; and any part or combination of parts that converts a weapon into a machine gun.

Before approving the bump stock design by Slide Fire, the ATF approved another design called the Akins Accelerator in 2006 but reversed its decision as the manufacturer went to market, the Associated Press reported. Federal regulators made the later determination because the device uses a spring that allows the stock to stay stationary while the gun moves. The use of the spring effectively made it a machine gun.

Jump ahead to 2010, Texas company Slide Fire received a determination letter from the ATF, saying its bump stock did not violate regulations defined in the NFA or GCA. “The stock has no automatically functioning mechanical parts or springs and performs no automatic mechanical function when installed,” wrote John R. Spencer, ATF chief firearms technology branch.

“In order to use the installed device, the shooter must apply constant forward pressure with the non-shooting hand and constant rearward pressure with the shooting hand. Accordingly, we find that the ‘bump-stock’ is a firearm part and is not regulated as a firearm under Gun Control Act or the National Firearms Act,” the letter continued.

Patents for the Akins Accelerator were later transferred Fostech Outdoors, a competitor of Slide Fire, which also received a determination letter in 2012 approving the design. The ATF informed the company (page 1 and page 2) that the device “is not a machine gun as defined under the NFA” and added that the classification would be void if it were manufactured with “an accelerator spring or any other non-manual source of energy which allows this device to operate automatically.”

The device became the subject of debate after a gunman used the device to spray gunfire into an audience of 22,000 at a concert on the Las Vegas strip on Oct. 1, killing 58 people and injuring almost 500 others. The incident spurred lawmakers on both sides of the aisle to express support for banning the item by updating federal law to allow for regulation of the device. Democrats filed a proposal but a bipartisan measure has not been filed yet.

Correction: We originally reported that Bill Akins’ patent was transferred to Bump Fire Stocks. The detail has been corrected. Updated Oct. 12, 2017 at 12:38 pm EST.