From gangster Tommy guns to Glock switches: The history of machine guns on U.S. streets

On Valentine’s Day 1929, four men connected with Al Capone’s Chicago gang killed seven rivals with Thompson machine guns, better known as Tommy guns .

The bloody massacre shocked the nation, making newspaper headlines across the country.

It was the beginning of gun violence involving machine guns in the U.S., a deadly trend quashed by laws only to re-emerge today with Glock switches, devices that turn ordinary handguns into even more deadly machine guns.

U.S. Army Brigadier General John Thompson invented his namesake Tommy gun in 1918, hoping it could end trench warfare during World War I. But the Tommy guns didn’t arrive before the war ended and later ended up with gangsters like Capone during the Prohibition era.

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At the time, gun laws in the U.S. were largely governed by states and municipalities. But as Tommy gun violence spread, President Franklin Roosevelt recognized that local laws did nothing to prevent Tommy gun sales across state lines.

Roosevelt initially hoped to ban machine guns through the first national gun-control law, The National Firearms Act of 1934. Gun rights advocates pushed back, however, and there was a compromise: the Firearms Act instead heavily taxed and regulated machine guns.

It largely worked, and federal regulations of machine guns remained unchanged until 1986, when Congress passed another law aimed at protecting U.S. gun owners. Part of that law, however, also banned civilian ownership of machine guns manufactured after May 19, 1986.

That created a limited supply of legal machine guns, putting prices far beyond the reach of most. In 2022, The Trace reported that basic models of machine guns can cost $10,000 online, but collector machine guns sell for more than $100,000.

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But the Glock switch could change that.

Venezuelan Jorge Leon has said he created the equivalent of the Glock switch in 1987, the year after the U.S. machine gun ban. He was 22 at the time and hoped his inexpensive creation could help the military and police in his country.

Ten years later, in 1996, Leon patented the switch in the U.S.

That patent expired in 2016, freeing anyone to use his detailed drawings and specifications for the simple device even though it remains illegal to use or possess in the U.S.

That appears to have changed everything.

In 2023, the ATF reported its agents confiscated 5,454 Glock switch-type converters between 2017-2021. It marked a 570% increase over a five-year period, the most recent data available.

Based on conversations with federal and local officials, the number of these switches has only continued to rise.

Leon, now 59, in June told ABC News he now regrets inventing the switch.

“After seeing and reading about all those deaths, those unnecessary deaths of youngsters, of police officers, of broken families, I don’t feel nice about that,” said Leon, who now designs medical technology.

This article originally appeared on Akron Beacon Journal: From gangster Tommy guns to Glock switches: The history of machine guns on U.S. streets