Cheap metal part turns regular guns into automatics

A piece of metal the size of a small coin that can convert a semiautomatic weapon into a fully automatic machine gun capable of firing up to 1,200 bullets a minute is increasingly being used in the United States, the agency responsible for firearms supervision said.

The "auto sear, Glock switch or chip" is being bought online or made with a 3D printer, said the Bureau of Alcohol, Tobacco, Firearms and Explosives. They cost under $100.

The ATF, as the bureau is known, said that over the past year-and-a-half, it had seized more than 100 modified guns in Memphis, Tennessee, and western parts of the state and Alabama. In 2021, it seized 1,500 weapons nationwide that used Glock chips, a huge jump from the 300 seizures in 2020.

Guns with the switches also have shown up in California and in Washington, DC, where the Metropolitan Police said that in the first six months of 2020, it recovered 10 guns modified with auto sears－the catch in a gunlock－and in the first half of 2021 the number doubled to 20.

In 1986, Congress passed the Firearms Owners Protection Act, which prohibits the import or manufacture of any new automatic weapons.

The switch devices are classified as machine guns by the ATF. Anyone found with one can face 10 years or more in prison. The switches are like bump stocks used on rifles to increase firing speed. Bump stocks became illegal in 2019.

Many of the auto sears are sold on the black market or are imported.

Mickey French, the special agent in charge of the ATF's Nashville, Tennessee, division, told an NBC television affiliate in May that auto sears are "hidden in how they are marketed", and that presents a "challenge to law enforcement".

The auto sear prevents the trigger on a gun from resetting so it can be pressed once to empty a magazine. While a Glock gun fires 15 rounds in 8.32 seconds, a Glock switch or auto sear turns it into an automatic that can fire 30 rounds in just 2.3 seconds.

Concern over the use of Glock switches comes amid heightened fears about guns following mass shootings at a school in Uvalde, Texas, and a supermarket in Buffalo, New York.

In April, a gunman armed with a modified Glock opened fire in Sacramento, California, killing six people and wounding 12 others.

In May 2020, Steven Carrillo, 32, a member of the anti-government group the Boogaloo Boys, shot at two security officers outside a federal building and courthouse in Oakland, California. He killed one and wounded the other using a homemade AR-15, which had been turned into a machine gun with an auto sear. He was sentenced to 41 years in prison.

On April 11, more than 40 members of Congress signed a letter urging the ATF to be more aggressive against the rise in auto sears and Glock switches.

On Sunday night, one teenager was killed and three adults were injured in a shooting in Washington, DC. The shooting occurred in an area filled with stores, restaurants and bars, police said.

This year, more than 20,000 people in the US have died due to gun violence, according to the Gun Violence Archive, which keeps track of such incidents as a public service.

Xinhua contributed to this story.