A surge of illegal homemade machine guns has helped fuel gun violence in the US

Communities around the U.S. have seen shootings carried out with weapons converted to fully automatic in recent years, fueled by a staggering increase in small pieces of metal or plastic made with a 3D printer or ordered online. Laws against machine guns date back to the bloody violence of Prohibition-era gangsters. But the proliferation of devices known by nicknames such as Glock switches, auto sears and chips has allowed people to transform legal semi-automatic weapons into even more dangerous guns, helping fuel gun violence, police and federal authorities said.

The (ATF) reported a 570% increase in the number of conversion devices collected by police departments between 2017 and 2021, the most recent data available.

The devices that can convert legal semi-automatic weapons can be made on a 3D printer in about 35 minutes or ordered from overseas online for less than $30. They’re also quick to install.

“It takes two or three seconds to put in some of these devices into a firearm to make that firearm into a machine gun instantly,” Dettelbach said.