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3-D Printing

Judge blocks 3-D printed gun files from going online

States sued over fears of untraceable plastic guns

by Alexander H. Tullo
August 1, 2018 | A version of this story appeared in Volume 96, Issue 32


A photo of someone holding a white plastic pistol.
Credit: Jay Jenner/TNS/Newscom
Officials are worried about 3-D-printed guns ending up in the wrong hands.

A federal judge in Washington state has issued a restraining order that will prevent Defense Distributed from sharing design files for firearms online. The second amendment advocacy organization had planned to make the blueprints, which instruct three-dimensional printers to make firearm parts out of polymers, available today.

3-D printed firearms are the subject of much dispute over their legality, public impact, and technical feasibility. In 2012, Defense Distributed started publishing design files for 3-D printed firearms such as the Liberator, a single-shot plastic pistol, as well as the lower receiver—a frame that holds components together—for the AR-15 semiautomatic rifle.

The State Department blocked distribution of the files on the grounds that it constituted an illegal export of technical data for arms. Invoking free speech, Defense Distributed sued, and the case wended through the courts until June, when the two parties settled.

Worried about untraceable weapons ending up in the wrong hands, state attorneys general have done everything they could to block the publication. Washington, seven other states, and the District of Columbia took the State Department and Defense Distributed to court to block the Aug. 1 dissemination of the files.

“As of that point, the files will be, practically speaking, irretrievable, because they will have been posted on the Internet—a bell that cannot be un-rung,” the suit said.

While the attorneys general got the restraining order they were looking for, the files in question are purportedly available elsewhere on the web, including on and

Some critics point out that 3-D printing is an impractical route to a firearm. Polylactic acid (PLA), acrylonitrile-butadiene-styrene (ABS), and other plastics available for home 3-D printers don’t have the properties necessary for reliable weapons.

“I understand that the underlying concern is that some disturbed individual equipped with a 3-D printer will be able to build or assemble a firearm with a few clicks, when in fact, this is still the realm of engineering hobbyists and tinkerers,” says Michael Guslick, an engineer who, in his spare time, designed a 3-D printed version of the lower receiver for the AR-15. “You can build a far more effective and reliable improvised firearm with $20 worth of materials from the hardware store plumbing department.”

However, Dayton Horvath, a principal at NewCap Partners and an independent consultant in additive manufacturing, isn’t so dismissive. PLA and ABS could work for the Liberator. And the materials are evolving. “You can go on Amazon and get better thermoplastic materials than have been available in the past,” he says.

Moreover, Horvath says printers that can turn nylon 12 powder into professional-grade parts can now be purchased for less than $10,000. Machines that print metal parts cost less than $50,000, though they require additional equipment, like a high-temperature oven, to produce finished parts.


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