NBC 7 Investigates: ‘Glock Switches' Convert Handguns Into Illegal Machine Guns

Pistols can be modified to unload more than a dozen bullets in under a second

On an early Sunday morning in April, downtown Sacramento sounded like a warzone. Bullets sprayed into crowds that were leaving an area known for nightlife. Six people lost their lives, and a dozen more were wounded. Police say one of the shooters was carrying a 9mm handgun, which had been converted to fire as an automatic weapon.

Pamela Harris, the mother of one of the victims who died, told the Today Show that bullet shell casings littered the street afterward.

“If you was down there and see all them bullets, everywhere, I mean that was a massacre,” Harrison said.

The illegal devices that convert semi-automatic weapons into machine guns go by many names: switches, auto-sears, and more. The effect is the same; a weapon that only fires a single bullet each time the trigger is pulled can now unload all the bullets in its clip by holding down the trigger.

NBC 7 Investigates reached out to the Los Angeles Field Office of the Bureau of Alcohol, Tobacco, Firearms and Explosives, which agreed to demonstrate how these devices work.

We met their team, including Special Agents Michael Hoffman and Jarrett Keegan, at a private outdoor gun range in San Diego County. Agent Hoffman is the Assistant Special Agent In Charge of the Los Angeles Field Division. Agent Keegan also serves as an agency firearms instructor.

They brought along 9mm Glock handguns and a switch. The small metal part is about the size of a marble and can be quickly attached to a gun.


After providing us with a safety briefing, Keegan put on a shooting demonstration. He fired his unaltered service weapon, unloading 17 bullets at a paper target. The trained marksman fired all those rounds in just under five seconds.

But when that illegal switch was added to the Glock, all 17 bullets left the weapon in a little more than one second.

The speed at which the gun fires also has a big impact on accuracy. 

“It feels like it’s running away from me, to be honest,” Keegan told us. “Like it feels, for a shooter it’s somewhat uncomfortable. I just feel like it’s out of control.”

That was evident by looking at the paper targets from both firing sequences. The bullet holes from the semi-automatic example were tightly grouped together, while they were all over the target or missed it entirely when it was fired as an automatic.

Agents told us that lack of accuracy presents a big danger to the public.

“Pistols are made to be concealed,” Keegan said. “For this pistol, this is something that’s made to go in my pants. So when I make this full auto, it doesn't have the weight, the heft - it wants to ride up. It’s not designed to do this out of the box. And so it feels real uncomfortable running this through a pistol.”

Hoffman told us weapons like these can fire up to 1,100 rounds per minute.

“That is just a lot of firepower going downrange,” Hoffman said. “Law enforcement is in a very dangerous situation when they come up against these types of firearms.”

The ATF says machine gun conversion devices are hitting the streets in record numbers. In 2017, the ATF says it recovered fewer than a hundred of them nationwide. But in 2021, that number jumped to more than 1,500. Switches are illegal in every state and on a federal level, with only a few exceptions.

A look at how powerful and quick the automatic Glocks are.
A look at how powerful and quick the automatic Glocks are.

“These devices, in and of themselves, are considered a machine gun,” Hoffman told us.

In order to possess a legal machine gun in the United States, it has to be registered with the ATF.

NBC 7 Investigates reached out to every local law enforcement agency and dug through dozens of police reports. We discovered these devices have turned up in our communities, including a February arrest of a juvenile in Chula Vista. That person was pulled over near the corner of Broadway Avenue and H Street. Inside the car, police say they found illegal drugs and a handgun converted into a machine gun.

It’s difficult to say just how many devices are being recovered across our area. NBC 7 Investigates learned most of the agencies aren’t collecting data in a way that they could get us the numbers in a matter of days or even weeks. That’s in contrast to ghost guns, where those numbers are readily accessible. Some of the smaller police departments, like Oceanside and National City, say they haven’t recovered any switches.

Hoffman says the ATF is seeing people with no criminal history trafficking these devices. They tend to be younger, in their 20s and 30s. He says they’re getting them online, and says the ATF is also concerned that 3D printers are being used to make switches. Hoffman says he’d like to see tougher penalties for possessing or trafficking these devices. Right now, the maximum time you can face for getting caught with a switch is 10 years.

NBC 7 Investigates also reached out to Glock multiple times to see what they had to say about these devices and how easily they convert their weapons into machine guns. We never heard back.

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