Cody Wilson made global headlines last year when he produced the first working 3D-printed pistol, which he called the “Liberator.” The files for the single-shot pistol were downloaded more than 100,000 times before the US Department of Defense locked his website and removed the files. That did not stop other 3D-printing pioneers from exploring what the technology could offer the world of gunsmithing, and numerous designs for firearm parts, accessories, and even whole guns surfaced in the months afterwards. Wilson, however, has been relatively quiet. Now the former University of Texas law student is once again making headlines with a new design: a personal CNC mill.

Ghost Gunner CNC MillOffered at the price of $1,200 (a $999 option for early adopters quickly sold out), the miniature CNC mill is offered online by Wilson’s company Defense Distributed. Wilson, who is known for naming his designs after issues in the gun control debate, has dubbed his new product the “Ghost Gunner.” The name is a reference to a bill in California that would have required that homemade or otherwise self-assembled guns be registered (the bill was vetoed by Governor Jerry Brown on Tuesday). While the Ghost Gunner can perform a variety of functions, Wilson and his company are highlighting its ability to “complete” what are referred to as 80 percent AR-15 lower receivers. Eighty percent lower receivers require additional manufacturing to turn into functional AR-15 parts, but are not legally considered firearms until they are complete.

“As shipped, Ghost Gunner can manufacture any mil-spec 80% AR-15 lower receiver that already has the rear take down well milled out. Lowers with non-mil-spec trigger guards that are otherwise mil-spec are also compatible,” states Defense Distributed’s website.

Ghost Gunner CNC MillVery little CNC knowledge is needed the run the device. To complete something like an 80 percent lower, all a user needs familiarity with is click-and-point software (as well as some 3D-printing basics). The box-shaped device—built out of A36 steel and 305 stainless steel—uses a drill bit to carve into whatever material is fed into it, whether it is wood, polymer, or aluminum. Wilson told Wired magazine that the ability to mill objects out of metal is what really separates the Ghost Gunner from almost anything else on the market.

As shipped, Ghost Gunner can manufacture any mil-spec 80% AR-15 lower receiver that already has the rear take down well milled out. Lowers with non-mil-spec trigger guards that are otherwise mil-spec are also compatible. Defense Distributed recommends using the 7075 Ares Armor Raw 80% Lower AR-15 Billet, available for purchase here.

Ghost Gunner is capable of manufacturing more than just firearm receivers. With Defense Distributed’s open source Physibles Development SDK (pDev), designers can distribute files via our ‘.dd’ file format, which contains all installation and assembly instructions, any required jig files to hold the part in place (that users can print with a 3D printer), and all machine definitions and code to physically manufacture a particular design.

To a casual user, the .dd file is a one-stop solution to manufacturing any aluminum physible that the public can design to fit into the build envelope. Defense Distributed will be developing in and supporting this format, and we are happy to publish your own innovations and contributions.

If you can assemble a firearm or operate a 3D printer, you can use Ghost Gunner.

Ghost Gunner ships fully assembled and ready to build right out of the box. No assembly is necessary and no programming is required. After installing the included software, you’ll be ready to manufacture publicly available .dd designs. Defense Distributed is committed to releasing future firearm design files, from the AR-15 to the AR-10 to the 1911, and then continuing with our own designs.

“Typically this has been the realm of gunsmiths, not the casual user. This is where digital manufacturing, the maker movement, changes things,” he said. “We developed something that’s very cheap, that makes traditional gunsmithing affordable. You can do it at home.”

It is also totally legal. The completion of an 80 percent lower receiver for personal use is completely within the law. The Ghost Gunner is also drawing interest from the tech crowd, many of whom see the potential in a personal CNC mill.

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The .dd file format is itself open source and not constrained to the Ghost Gunner or Defense Distributed; any user can define any existing machine’s specific parameters via the machine parameters list. A single file can contain specific code and installation instructions for any number of machines. A user with both a Ghost Gunner and a Tormach P1100 could manufacture a particular .dd file on either machine and manufacture the same physible with zero additional user knowledge, as only the instructions required for a particular machine are revealed to the end user. The .dd file format is a CNC response to 3D printing’s universal .stl file format.

For those who have a favorite CAM program and don’t want to share your design via our new file format, Ghost Gunner will also accept TinyG code from any CAM program.

“What’s cool here is that the price of a CNC mill capable of doing this just dropped from tens of thousands of dollars to $999 seemingly overnight,” wrote one reddit user. “Give this technology 5 years, and we’ll all have desktop CNC mills for $300 bucks [sic]. There is a lot to get excited about here.”

Ghost Gunner is a non-profit open source hardware effort by Defense Distributed. Ghost Gunner builds on the open source community’s existing hard work, including the gshield 3 axis motion hardware, the grbl g-code parser and motion controller, and the legendary Arduino microcontroller. All GhostGunner schematics and design files will be published into the public domain. Defense Distributed decided to build our own machine from the ground up.

We found existing CNC machines too expensive, too DIY, or too inaccurate to manufacture firearms for the casual user. By miniaturizing the build envelope to just large enough to mill common firearm receivers, we were able to improve rigidity, reduce material cost and simultaneously relax some design limits, allowing us to sell an inexpensive machine with more than enough accuracy to manufacture firearms.


  • Ghost Gunner

  • Machinable dimensions: 175 x 75 x 60mm (~6.75 x 2.95 x 2.35″)

  • Maximum part dimensions: 230 x 90 x 100mm (~9.05 x 3.50 x 3.90″)

  • Overall footprint: 330 x 280mm (~13 x 11″)

  • Weight: 20kg (~45 pounds)

  • Spindle Speed: 10,000+ RPM (Final Value TBD)

  • Requirements: Windows 7 or higher. Mac version TBD.



You can see the teaser video for the Ghost Gunner below: