In America, a small piece of 3D-printed plastic can turn a semi-automatic handgun into a fully automatic machine gun. In the rest of the world, where guns are harder to get, people are just 3D printing the whole weapon.

Around four years ago a German man named Jacob Duygu designed a semi-automatic carbine with a computer and 3D printed all the pieces. He called it the Fuck Gun Control 9, or FGC-9, because he didn’t like Europe’s restrictive gun laws, and the weapon fired 9mm bullets.

Now, Duygu—known online as JStark—is dead, but his weapons are everywhere. According to a new report from The New York Times, authorities have found the FGC-9 “in the hands of paramilitaries in Northern Ireland, rebels in Myanmar and neo-Nazis in Spain.” This was what Duygu would have wanted.

“I have a responsibility to make sure everybody has the option to be able to get a gun,” Duygu told journalist Jake Hanrahan in 2020. “The way they use it is up to them.”

Duygu taught himself how to manufacture and build the gun himself, and he helped build a community online called Deterrence Dispensed, which publishes guides and plans for 3D-printed firearms. One of the biggest names in that community today is Ivan the Troll, who helped Duygu design updated versions of the FGC-9.

According to the Times, Ivan the Troll is a 26-year-old gunmaker in Illinois named John Elik. “Mr. Elik, in his email to The Times, said it was wrong to focus on ‘European cops complaining about a small number of guns being recovered,’ and shootings in which nobody was injured, ‘rather than the gun’s use as a tool of liberation.’”

Meanwhile, in America, it’s easier to just buy a semi-automatic handgun and use a 3D printer to convert it into a fully automatic weapon. Over the past year, the Justice Department, ATF, and local law enforcement across the country have sounded the alarm about so-called machine gun conversion devices (MCDs) or “glock switches.”

An MCD is a small piece of metal or plastic that’s attached to the back of a semi-automatic pistol. In a normal Glock, you pull the trigger, the gun fires, and the slide mechanism ejects the cartridge and resets the trigger. The MCD pushes a small piece of metal or plastic into the gun so the trigger never resets. Pulling the trigger on a Glock with an MCD will unload all of its rounds in seconds.

American law enforcement agencies have said they’ve seen a marked increase in MCDs in gun crimes over the last few years. The device is federally illegal and many states have passed additional laws against them. But they’re also small, cheap, and easy to manufacture with a 3D printer.

On September 6, Deputy Attorney General Lisa Monaco decried MCDs in a speech and said that America had to do more to get them off the street. “I am establishing the Justice Department’s Action Network to Terminate Illegal Machinegun Conversion Devices—or ANTI-MCD for short,” she said. “I’ll be asking the ANTI-MCD Committee for recommendations on how to best deploy Department resources to reduce the proliferation of MCDs.”

Monaco said that, ultimately, the only way to stop MCD was to stop them from being made in the first place. “We need to engage software developers, technology experts, and leaders in the 3-D printing industry to identify solutions in this fight,” she said. “And we have to do all of this while raising public awareness about the deadly threat posed by MCDs.”

There was no mention in Monaco’s speech of tackling the problem of the guns themselves which the MCDs modify.