This is my ghost gun. To quote the rifleman's creed, there are many like it, but this one is mine. It’s called a "ghost gun"—a term popularized by gun control advocates but increasingly adopted by gun lovers too—because it's an untraceable semiautomatic rifle with no serial number, existing beyond law enforcement's knowledge and control. And if I feel a strangely personal connection to this lethal, libertarian weapon, it's because I made it myself, in a back room of WIRED’s downtown San Francisco office on a cloudy afternoon.

I did this mostly alone. I have virtually no technical understanding of firearms and a Cro-Magnon man’s mastery of power tools. Still, I made a fully metal, functional, and accurate AR-15. To be specific, I made the rifle's lower receiver; that's the body of the gun, the only part that US law defines and regulates as a "firearm." All I needed for my entirely legal DIY gunsmithing project was about six hours, a 12-year-old’s understanding of computer software, an $80 chunk of aluminum, and a nearly featureless black 1-cubic-foot desktop milling machine called the Ghost Gunner.

The Ghost Gunner is a $1,500 computer-numerical-controlled (CNC) mill sold by Defense Distributed, the gun access advocacy group that gained notoriety in 2012 and 2013 when it began creating 3-D-printed gun parts and the Liberator, the world’s first fully 3-D-printed pistol. While the political controversy surrounding the notion of a lethal plastic weapon that anyone can download and print has waxed and waned, Defense Distributed's DIY gun-making has advanced from plastic to metal. Like other CNC mills, the Ghost Gunner uses a digital file to carve objects out of aluminum. With the first shipments of this sold-out machine starting this spring, the group intends to make it vastly easier for normal people to fabricate gun parts out of a material that's practically as strong as the stuff used in industrially manufactured weapons.

The Ghost Gunner may signal a new era where the barrier to building an untraceable semiautomatic rifle is lower than ever before.

In early May, I got a Ghost Gunner, the first of these rare CNC mills loaned to a media outlet, and I tried it out. I'm going to give away the ending: Aside from a single brief hardware hiccup, it worked remarkably well. In fact, the Ghost Gunner worked so well that it may signal a new era in the gun control debate, one where the barrier to legally building an untraceable, durable, and deadly semiautomatic rifle has reached an unprecedented low point in cost and skill.

But the Ghost Gunner represents an evolution of amateur gun-making, not a revolution. Homebrew gunsmiths have been making ghost guns for years, machining lower receivers to legally assemble rifles that fall outside the scope of American firearms regulations. In fact, when we revealed the Ghost Gunner’s existence last year, the comments section of my story flooded with critics pointing out that anyone can do the same garage gunsmithing work with an old-fashioned drill press.

I could hardly judge the fancy new CNC mill in WIRED’s office without trying that method too. Or for that matter, Defense Distributed’s previous trick, building gun parts with a 3-D printer. Before I realized exactly what I was getting into, I determined to try all three methods in a ghost-gun-making case study. I would build an untraceable AR-15 all three ways I’ve heard of: using the old-fashioned drill press method, a commercially available 3-D printer, and finally, Defense Distributed's new gun-making machine.

All the components of my AR-15, including my homemade lower receiver, the gleaming aluminum piece. Josh Valcarcel/WIRED

The Ingredients of a Ghost Gun

Almost no one builds a ghost gun from scratch, and I didn’t either. The shortest path to building an untraceable AR-15 requires only that you build one relatively simple component yourself, a part that’s become the focus of a fierce gun control controversy: the lower receiver.

US gun regulations have focused on the lower receiver because it’s the essential core of a gun: It holds together the stock, the grip, the ammunition magazine, and the upper receiver, which includes the barrel and the chamber where the cartridge is detonated. As Doug Wicklund, senior curator at the NRA museum explained to me, the lower receiver always has carried the serial number because it's the part that remains when the others wear out and are replaced. Like the frame of a bicycle or the motherboard of a computer, it's the nucleus of the machine around which everything else is constructed.

My AR-15's homemade lower receiver. Josh Valcarcel/WIRED

It’s worth noting that buying an AR-15 in the US isn’t hard. But the privacy-minded—as well as those disqualified from gun purchases by criminal records or mental illness—can make their own lower receiver and purchase all of the other parts, which are subject to nearly zero regulation. I ordered every part of my AR-15 but the lower receiver from the website of Ares Armor, a Southern California gun seller that doesn’t require any personal information beyond a shipping address. If I wanted to hide my purchases from my credit card company, I could have paid in bitcoin—Ares accepts it.

There's even a way to anonymously buy that highly regulated lower receiver—almost. Like many gun vendors, Ares sells what's known as an "80 percent lower," a chunk of aluminum legally deemed to be 80 percent of the way toward becoming a functional lower receiver. Because it lacks a few holes and a single precisely shaped cavity called the trigger well, it's not technically a regulated gun part.

Buying or selling a ghost gun is illegal. Making one remains kosher under US gun control laws.

Machining the last 20 percent myself with a CNC mill or drill press would allow me to obtain a gun without a serial number, without a background check, and without a waiting period. I wouldn’t even have to show anyone ID. Law enforcement would be entirely ignorant of my ghost gun’s existence. And that kind of secrecy appeals to Americans who consider their relationship with their firearms a highly personal affair that the government should keep out of.

Controversy swelled around ghost guns when John Zawahri, an emotionally disturbed 23-year-old, used one to kill five people in Santa Monica in the summer of 2013. Even so, they haven't been outlawed; buying or selling a ghost gun is illegal, but making one remains kosher under US gun control laws. California state senator Kevin Deleon introduced a bill to ban ghost guns last year, following the Santa Monica mass shooting. Governor Jerry Brown vetoed it a few months later.

But as the shouting match over ghost guns gets louder, few of the shouters have actually tried to make one. Even fewer have tried to test how the evolution of a new set of digital “maker” tools is changing that gun control question.

So over the course of one strange week in WIRED’s office, that's what I set out to do. Here's how it all went down.

The drill press, jigs and vise I used in my first attempt to finish an 80 percent lower receiver. Josh Valcarcel/WIRED

The Drill Press

Remember when I said I know nothing about using power tools? Unsurprisingly, this portion of my gunsmithing experiment didn't go well.

Step one: Acquire a drill press, a massive stand-alone drill meant to cut the aluminum features out of my 80 percent-lower receiver. One $250 rental fee later, two colleagues helped me haul a drill nearly 6 feet tall down to our building's loading dock, a dark and chilly concrete space occupied by a pair of large Dumpsters. I'd paid Ares $97 for a set of steel-carbide drill bits and end mills—tools that act like bits but also can cut sideways like a milling machine—all of which the company recommended I use with the drill press to do the job. I paid another $110 for a set of steel jigs, metal stencils that would guide the machine as I tried to mill and drill precise shapes.

As the drill bit chewed into the block, I tasted fine aluminum dust between my teeth.

All that planning and spending, it turned out, couldn't compensate for my utter lack of even high-school-level shop skills. Before I'd even begun, I realized I had the wrong sort of vise, and we had to drive an hour and drop $80 to pick up another one. Then there was the drilling itself—which, it would turn out, is not as easy as it looks on the Internet.

I reviewed my lower-receiver drilling basics on YouTube one last time, put on latex gloves and eye protection, screwed the steel jigs around my slug of aluminum, tightened the clamps, and hit the chunky green power button.

As the drill bit chewed into the block, I felt a rush of excitement and tasted fine aluminum dust between my teeth. The bit threw off metal shavings and left behind a gleaming, polished crater. But my elation faded as I realized how badly I was mangling the trigger well. No matter how hard I cinched it down, the vise shuddered constantly, moving the aluminum piece. The holes I was cutting veered off until they were practically diagonal.

When I switched to the end mill to clean up the spaces between the pits I'd created, I found they were mostly at different depths: The drill bit had somehow moved up and down, and I hadn't noticed. The bottom of the cavity I'd made began to resemble the surface of the moon. Meanwhile, the massive machine protested loudly, shaking like a train about to derail. Throughout this ordeal, WIRED video producer Patrick Farrell, a former bike mechanic who probably could have offered helpful advice, watched me struggle from behind his camera with a restrained smirk. The unwritten rule: I was in this alone.

I kept at it for five and a half hours. Then the head of the drill press—the part that holds the bit, which I'd later learn is called the "chuck"—fell off. I had no idea whether this was supposed to happen as a kind of fail-safe, or if I had destroyed an expensive piece of equipment rented with Farrell’s credit card. I screwed the chuck back in, and after a few more minutes of metal-on-metal violence, it dropped off again. (I still don’t know if I damaged the drill press, but a gunsmith later explained to me that it likely wasn't designed to handle the lateral pressure of using it as a milling machine.)

That's when I gave up. I had nothing to show for my labor but a sad metal block scarred by a maze of crooked channels. Well, that and a left hand bristling with tiny aluminum shards where my latex glove had split.

A 3-D printed lower receiver on the print bed of a Makerbot Replicator. Josh Valcarcel/WIRED

3-D Printing

I left the grease-soaked drill press in WIRED's loading dock, headed back upstairs, and pulled a $2,800 Makerbot Replicator from its box. It felt like the elevator was a time machine shortcutting about a century of technological progress.

I plugged in the 3-D printer, followed a series of delightfully idiotproof instructions, and in minutes was test-printing a tiny white coffee table. Soon I was ready to start making gun parts; no obscure YouTube instruction videos, calipers, jigs, or aluminum splinters required.

I found the blueprint for a printable, reinforced AR-15 lower receiver on The Pirate Bay. It was one of dozens of gun parts available for download in the rogue BitTorrent repository's "physibles" section, a part of the site presciently created in 2012 to host controversial digital blueprints other sites wouldn't or couldn't. In fact, the file I downloaded had been created by Defense Distributed in 2013, but the group had pulled it from its own website after the State Department threatened to prosecute the group's staff for weapons-export-control violations.

It took a few minutes to torrent the lower receiver file. I opened it in Makerbot's printing application, centered it on the app's digital representation of the machine's print bed, and clicked print. The printer’s motors began to whir, and within seconds its print head was laying out extruded white plastic in a flat structure that vaguely resembled the body of a semiautomatic rifle. As the workday ended and WIRED's office emptied, I found myself sitting alone in a darkening room, transfixed by the gun component slowly materializing before me.

At one point, six hours into the nine-hour print job, the Replicator's print head overheated and took some time to cool down. That required pressing one more button on the machine. I didn't touch it again. The next morning I came back to the still-dark room and found a finished, eerily translucent lower receiver glowing inside the Replicator's LED-lit chamber.

As science-fictional as that process felt, the results were flawed. When I pried the finished lower receiver off the print bed, one side was covered in support material meant to prevent the hot plastic structures from collapsing before they solidified. Snapping and scraping off that matrix of plastic was a long, messy process. I tried using a knife, cut my thumb, and bled all over one side of the rifle body. And the same support materials also filled tiny holes in the piece, in some cases choking the delicate threads meant to accept metal screws.

It's clearly possible, based on YouTube evidence, to 3-D-print AR-15 lower receivers that are capable of firing hundreds of rounds. But mine wasn't so practical; I wouldn't know it until I visited a gunsmith two days later, but I'd eventually give up on assembling a gun out of that plastic-printed lower receiver long before it was anywhere close to a becoming a functional weapon.

The Ghost Gunner, with an 80 percent lower receiver bolted inside. Josh Valcarcel/WIRED

The Ghost Gunner

The new generation of “maker” tools like 3-D printers and CNC mills have been lauded as machines that allow anyone to make anything. But from my first moments using the Ghost Gunner, it was clear: This is a machine designed to make a gun.

Defense Distributed’s CNC mill is a simple black cube, with two tiny stepper motors sticking out of two of its six sides. As if to underscore the power contained in its microwave-sized footprint, the machine was so heavy I could barely lift it from its box. When I did haul it onto a table, I was struck by the lack of branding or the toylike LED lights and buttons of the Replicator. Its stark simplicity mirrors the unmarked gun parts it's designed to create.

Eventually, it felt much more like the Ghost Gunner had programmed me to be its gun-making tool than vice versa.

The Ghost Gunner works with either of two pieces of software: GRBL, an open source, general-purpose milling application, and DDCut, a Windows-only gun-milling program created by Defense Distributed and recommended by the group for anyone other than advanced CNC mill users. The Ghost Gunner also comes with the DDCut instruction file for milling an AR-15 lower receiver, shipped on a USB thumb drive in the box. (Putting it on the Internet, as with the 3-D-printable files, might have prompted the State Department to threaten Defense Distributed with prosecution again for weapons-export-control violations.)

I installed DDCut and found that for its primary purpose of finishing a lower receiver, the Ghost Gunner is absurdly easy to use—mostly because I was never given the chance to make any choices. Once DDCut began running the AR-15 file and cutting into my 80 percent-lower receiver, my only interaction with the software was clicking "next" through a 22-step set of instructions and then doing things to the aluminum part that the software told me to do.

For one hour-long stretch in that process, I was given nothing to do but simply admire the Ghost Gunner as its blurred, cylindrical blade cut away the gun's trigger well with inhuman precision. At other times it seemed to alternate between carving aluminum and assigning me tasks like changing the lower receiver's position, tightening and loosening bolts, switching the end mill to a drill bit, or even vacuuming up the aluminum shavings that piled up in and around the machine. Eventually, it felt much more like the Ghost Gunner had programmed me to be its gun-making tool than vice versa.

The Ghost Gunner drills out a lower receiver's trigger pin hole. Josh Valcarcel/WIRED

Over those hours, I couldn't help but appreciate the beauty of the Ghost Gunner's design and engineering. As it patiently removed metal, the aluminum piece and the cutting tool moved in robotic, mesmerizing patterns. The noises the machine produced alternated between high-pitched shrieking and low groans that echoed through the WIRED newsroom and elicited complaints from neighbors. But during quieter lulls, the Ghost Gunner also emitted a series of rising and falling harmonics, produced by vibrations of the mill's stepper motors, that sounded like a kind of alien melody. My editor, Joe Brown, who came into the room to watch the machine at work, remains convinced the machine was programmed to play a piece of composed music.

When it was only three steps away from finishing its full process, however, the Ghost Gunner hit a serious snag. The probe the mill uses to measure the lower receiver's location malfunctioned, and the machine locked itself. To get it moving again, I had to break the rules of my experiment and call Cody Wilson, Defense Distributed's founder, to seek advice. At first he told me I'd have to rerun the entire process—close to four hours of wasted time. "It's a design flaw," Wilson admitted. "If it stops, it has to start again from the beginning."

But Wilson soon came up with a better plan and sent me a new file that rehearsed only the last portion of the AR-15 cutting process. Twenty minutes later I pulled from the machine the shining, perfect body of a semiautomatic rifle, as warm as if it were some baked good fresh from the oven.

My fully assembled AR-15. Josh Valcarcel/WIRED

Assembly

The Ghost Gunner's lower receiver looked obviously superior to my 3-D-printed one—and even more obviously superior to the hot mess of uneven aluminum I'd chewed up with the drill press. But before assembling the full weapon, I wanted an expert opinion. So I visited Bay Area Gunsmithing, a sunny garage in Novato, California, populated by two professional gunsmiths, a very impressive collection of ordnance, and a gracefully aging dachshund named Ruth.

When I showed my manually drilled lower receiver to Nathan Rynder, the shop's owner, he dismissed it immediately. The hammer and trigger wouldn't fit into the narrow, winding gorge of the trigger well I'd created, and I hadn't even gotten as far as drilling holes for the selector and trigger pins. (He did note that he'd seen worse attempts, including a customer who had brought him a lower receiver with a gaping, unintended orifice drilled through its side.)

I was more surprised when Rynder insulted my 3-D-printed lower receiver. "This is not ready to rock," he said, skeptically probing the part's details with his fingers. He pointed out that the blueprint had misplaced something called a "takedown pin hole," and he made a further to-do list of necessary fixes before it could be assembled. "You'd need to thread in a pistol grip, clean out the buffer tube threads, clean up everything a pin went through," Rynder said. "You’d need several hours of labor to clean this thing up."

Just the idea of a 3-D-printed lower receiver bothered him; if the ring that held on the buffer tube and stock (the big loop at the back of the receiver) were to break, he pointed out, it could unleash a large and powerful spring inches from the shooter's face. "It scares me," Rynder said.

My Ghost Gun Budget

Building an untraceable AR-15 with the Ghost Gunner is pricier than it would be with a traditional drill press. But it requires far less skill than that manual method and costs less than creating the gun with a typical 3-D printer.

Drill Press Method

JET drill press rental: $250

End mills/drill bits: $97

Slide Vise: $80

80 percent lower jigs: $135

80 percent lower receiver: $68

Upper receiver: $550

Lower receiver parts kit:

(trigger, hammer, grip, etc) $75

Stock: $63

Magazine: $16

Total: $1,334

3-D Printer Method

Makerbot Replicator: $2,900

Plastic spool: included

Upper receiver: $550

Lower receiver parts kit:

(trigger, hammer, grip, etc) $75

Stock: $63

Magazine: $16

Total: $3,604

Ghost Gunner Method

Ghost Gunner: $1,500

80 percent lower receiver: $68

Upper receiver: $550

Lower receiver parts kit:

(trigger, hammer, grip, etc) $75

Stock: $63

Magazine: $16

Total: $2,272

My Ghost Gunner–milled AR-15 body, by contrast, got a stoic nod of approval. Rynder—who, allow me to stress, makes guns for a living—wasn't exactly wowed that I'd produced a functional, essentially flawless lower receiver. But he gave me the go-ahead to build it into a full rifle. "It's safe to assemble, safe to fire," he said. "Yes, you could put this together and it would be ready to go."

Over the next hour in Rynder's shop, I constructed my AR-15. This was harder than Forrest Gump makes it look. But I persisted, learning the process as I went by watching a YouTube video from Ares Armor a few seconds at a time. (At a couple of points, Rynder couldn't help but point out that I had inserted a part backward or give me an unsolicited hint. I suppose this was cheating in my one-man gunsmithing experiment, but unfortunately Rynder was a very friendly, helpful, and competent person.)

When I finally slotted in the pins to attach the upper receiver—a component that looks much more like a gun than the lower receiver and whose total lack of regulation is, frankly, bizarre—they made a pleasant chink. My AR-15 was complete.

I looked down at the fully built rifle and something in my brain shifted. I realized that the abstracted parts I'd been fiddling with had turned into an object capable of killing someone. My lower receiver had transformed from a "gun" in a legal sense to a "gun" in a very practical sense.

I remembered that I should start being careful where I pointed it.

Firing my AR-15. Josh Valcarcel/WIRED

Shooting

Three days later, at a private range in Richmond, California, a half hour from Rynder's shop, I loaded my AR-15 with a 10-round magazine of .223 caliber ammunition and fired it for the first time. I pulled the trigger hesitantly as I aimed at a piece of cardboard 50 yards away. The deafening blast silenced the tweeting of nearby birds and echoed around the range's wooden walls as the rifle's stock dug into my shoulder. I could see a tiny hole in the cardboard. A plume of dust rose from the dirt berm behind it.

"Well, it goes bang," Rynder said.

I fired again. Then three more times. Then I emptied the magazine. Then I reloaded and emptied another one.

Halfway through the next magazine, I pulled the trigger but got nothing but a soft click. The rangemaster, who happened to be a former winner of the shooting competition reality TV show Top Shot named Chris Cheng, diagnosed that the upper receiver had jammed and needed to be lubricated—a common problem with new rifles. He opened it up and doused the bolt and buffer parts in grease, then put the upper receiver back on.

My rifle performed perfectly for the rest of the morning. After our video team fired the rest of the 40 rounds I'd brought, Rynder walked over to the neighboring range and convinced the friendly local SWAT team members practicing there to give us another 60 rounds. We shot those too. The gun didn't misfire again.

Exorcising My Ghost Gun

The day after that shooting field trip, I had a flight home to New York. Taking my ghost gun on a plane—legally, three ghost guns, in fact, since I had created three lower receivers—seemed unwise. I couldn't leave them in WIRED's office in San Francisco either, because that might count as legally transferring ownership of the unserialized guns, which is a felony. I considered destroying them with a hacksaw, but regulations posted online by the Bureau of Alcohol, Tobacco and Firearms seem to demand that a lower receiver be destroyed with a blowtorch, removing enough metal that it can't possibly be welded back together.

The testfiring target. Josh Valcarcel/WIRED

So instead I decided to surrender my three lower receivers to the local police. I disassembled my AR-15 and left a large box containing all of the parts except the lower receivers on my editor's chair. Then I walked down the street to the police station in San Francisco's SoMa neighborhood and told the lady at the front desk I wanted to hand over some firearm components. She gave me a puzzled look and asked me to sit down.

Forty minutes later, two cops emerged from a door and asked what I was doing there. I explained and showed them the three lower receivers. They examined them with expressions that were simultaneously quizzical and bored. I asked them if it was common to see AR-15 lower receivers like these: homemade, with no serial numbers. "I've never seen this before," one of them said.

The cops gave me a handwritten receipt for the three weapons I'd turned in, as if to definitively show that these were no longer outside of law enforcement's awareness or control: They now had a number. Then they took my lower receivers behind their locked door and I said goodbye to my ghost gun.

When this story published, the Ghost Gunner still sat in a storage room of WIRED's office a few blocks away. It's ready to make another lower receiver at any time. And Defense Distributed has already sold more than a thousand of their gun-making boxes, each one a tiny, easy-to-use, anarchic rifle factory.

In other words, to paraphrase the rifleman's creed again, this ghost gun was mine. But there will be many like it.

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