The Bureau of Alcohol, Tobacco, Firearms and Explosives is worried about a new trend on the streets -- a device that turns pistols into machine guns.

The ATF says it's tiny, but it's causing big problems.

What You Need To Know

  • The Glock switch device is becoming a new trend on the streets, officials say, turning pistols into machine guns

  • The auto sear is also known as a Glock switch, or switch, on the streets

  • It allows for a 30 round magazine to be unloaded in less than three seconds

A conventional semi-automatic weapon requires the trigger to be pulled each time a bullet is fired. But that very same weapon can be converted into a machine gun if it is equipped with an auto sear, known on the street as a "Glock switch" or just "switch."

“You pull the trigger once in, everything in the ammunition magazine gets fired," said ATF senior special agent Sean Martineck.

In less than three seconds, a 30-round clip can be unloaded, turning a semi-automatic into an instant machine gun. To make matters worse, officials say it’s a shoddy device that’s not accurate.

“These are put in pistols [or] handguns,” Martineck said. “Handguns are not made to be shot full auto, which makes it even harder to operate the gun.”

In a demonstration, Martineck shot right on target using a non-switched weapon. But when the auto sear was attached, accuracy was impossible, and that’s with a skilled shooter. “What we see is bullets flying all over neighborhoods [and] into houses. And you know, there are people outside [so] it's not a good combination.”

It makes the Glock switches that much more deadly in the hands of criminals.

“It's definitely an emerging trend that we are seeing in law enforcement,” Martineck said. “So it's something new.”

If somebody is found in possession of an auto sear, they could be charged federally for possession of a machine gun and that can bring up to 10 years in prison.

Martineck says the switches can cause mayhem.

“I’m very concerned considering the rise in violent crime with the use of firearms across the country,” he said. “Putting these out there [is] just going to magnify that."