A growing number of seizures of weapons made at home from 3D printed parts are ringing alarm bells among European police about an emerging threat.

For now, interest from far-right activists may be limited, analysts say — and fears of a society awash with self-expression guns remain far-fetched.

But homemade guns have become more widespread since 2013, when a US gun enthusiast first showed off a mostly 3D-printed handgun and shared its design online.

As recently as September, Icelandic police said they had arrested four people suspected of planning a “terrorist attack” and confiscated several 3D-printed semi-automatic weapons.

In the same month, Spanish authorities discovered an illegal arms workshop owned by a man in his forties in the Basque Country.

This finding was followed by two more such cases in the country in 2021.

In addition to two 3D printers, the police on the Spanish Canary Islands found literature and manuals by white racists on the subject of urban guerrillas.

And in the northwestern city of A Coruna, police uncovered a man on the verge of completing a homemade assault rifle.

“The rapidly developing advanced technology could mean that this becomes a bigger threat in the near future,” said Ina Mihaylova, a spokeswoman for the European police agency Europol.

While traditional guns are easily traceable thanks to their serial numbers and hallmarks, these “house-printed” models are less easy for authorities to trace.

At the moment, “there is still a big difference between the quality of the professionally manufactured weapons available in the criminal market and the 3D printed/homemade weapons,” Mihaylova said.

“3D printed firearms that are made entirely of plastic typically cannot withstand the pressure of live ammunition,” she added. You need metal barrels, chambers or firing pins.

But Christian Goblas, a ballistics expert at France’s University of Rouen, said “metal 3D printing” could become affordable in the next decade – which could make homemade weapons more durable and reliable.

With its 3D parts and metal firing pin, the 2013 “Liberator” pistol demonstrated by self-proclaimed “crypto-anarchist” Cody Wilson in 2013 featured a crude single-shot weapon of the same name being air-dropped at French resistance fighters during World became war II.

Wilson posted instructions for the gun online, sparking alarm in the United States with its already lax gun control and history of deadly mass shootings.

Since then, 3D printers have become cheaper and more blueprints have been published on the so-called dark web.

Rajan Basra, senior research fellow at the London-based International Center for the Study of Radicalization (ICSR), said nonetheless that 3D gun printing remained mostly a curiosity for firearms fans or libertarians.

Even in countries with strict gun restrictions, there are better options for gun seekers: In France, you can get a Kalashnikov assault rifle on the black market for between 500 and 1,500 euros.

To a lesser extent, DIY weapons are also attractive to “terrorists,” far-right militants and gangsters, Basra added.

Eleven out of 12 recent seizures in Europe have involved far-right activists, he stressed.

One of the most famous applications of weapons with 3D printed parts took place in Germany in 2019.

A gunman has killed two people in the eastern city of Halle after failing to break into a synagogue. Before the attack, he had put a racist, misogynistic and anti-Semitic manifesto online.

A video the attacker took of his killing spree showed him repeatedly struggling with gun jams.

“At least I demonstrated how useless improvised weapons are,” he was heard saying at one point.

Blyth Crawford, another researcher at ICSR, said the attack was an exceptional case.

In online discussions by some right-wing extremists, “3D printed firearms are not yet considered a serious alternative to regular firearms for conducting a mass shooting, as they are considered comparatively untried,” he said.

Jacob Ware, a counterterrorism researcher at the Council on Foreign Relations, agreed that not all of these extremists were enthusiastic about the labor-intensive manufacture of a weapon.

For some, it was “fundamentally groundbreaking in opening new doors for terrorists without access to firearms.”

But others derided the technology “as only relevant to those who failed to stockpile weapons in preparation for … government tyranny”.

Extremists may see other emerging technologies, such as drones, as more promising for their purposes.

“It’s unlikely that 3D printing is the future of terrorism for now,” Ware said.

However, “legal systems should move forward … to ensure gun control rules are not circumvented before it’s too late,” he added.