We 3D-Printed Luigi Mangione’s Ghost Gun. It Was Entirely Legal

For the last hour, in a backroom of a gun range in Arabi, Louisiana, I’ve been building Luigi Mangione’s gun. Well, not his, in the literal sense. The not-quite-finished firearm in my hands is very much mine: I was the one who pushed “print” on a 3D printer the prior evening and then, this morning, pulled the gun’s finished frame out of that mini-fridge-sized appliance. And I’m the one now struggling with the trickier task of attaching to that precisely contoured chunk of matte-black plastic all the metal and polymer components that will make it a fully functioning, semi-automatic pistol.

This weapon I’m constructing is, however, intended to be an exact clone of the partially 3D-printed gun that Mangione allegedly used to kill UnitedHealthcare CEO Brian Thompson in New York City in December, down to the stippling on the weapon’s plastic grip. I’ve come to this makeshift workshop on the outskirts of New Orleans with the goal of printing, assembling, and test-firing that very same model of handgun, complete with the 3D-printed silencer Mangione allegedly screwed to its muzzle.

The intention of this experiment is to see for myself just how far 3D-printed guns have come. I want to know if it’s true that the apparent murder weapon in the most high-profile assassination in recent memory can, in 2025, be made in the privacy of a garage by essentially anyone, without facing any gun control whatsoever or even breaking any laws.

The 3D printing, it turns out, was the easy part. Now I’m in the midst of the finicky process—something like assembling a very small piece of Ikea furniture—of building onto my homemade handgun frame the rest of a gun’s components, all ordered off the internet. This includes everything from the trigger assembly to the slide and barrel that ride on top of the Glock-style pistol’s plastic-printed body.

My guide on this journey, given that I have very little idea what I’m doing, is a 3D-printed-gun aficionado and YouTuber who calls himself Print Shoot Repeat, or PSR. He’s sitting to my right—dressed in a black hoodie along with the trademark black mask and mirror goggles that he wears to protect his identity—patiently offering instructions as I fumble with small parts.

As I approach the final step in the gun’s assembly, he shows me how to pull its trigger so that the slide can fit onto metal rails I’ve slotted into my printed frame. Then PSR watches as I struggle to pull that top half of the firearm into position. Suddenly, the slide seems to stop resisting and slips into place.

“Yep, now pull it back as hard as you can,” PSR tells me through his mask. I yank back on the chunk of metal, exposing the empty chamber that will soon be filled by a 9-millimeter round. “Now let it go.”

The spring-loaded slide snaps forward with a loud click. Only then do I notice that all the people in the room—the video crew filming all of this and the gun range employees who have become curious about our experiment—are standing up to watch the somewhat unnerving moment when a new DIY firearm comes into being.

“Alright. Now we’ve got a gun,” PSR says. “Just make sure you don’t point it at anyone.”

As strange as this experience may have been, it felt familiar. That’s because, 10 years ago, I had done it all before.

In 2015, in a quiet backroom of WIRED’s San Francisco office, I made an AR-15 “ghost gun”—a fully functioning semi-automatic rifle. Just like the Glock-style handgun I would construct in Louisiana a decade later, that rifle was a “ghost gun” in the sense that it had no serial number and was built entirely in private, without any background check, without showing anyone ID, and without making any government agency aware of its existence.

Ghost guns take advantage of a kind of loophole in US federal gun control laws: Only the central component of a firearm onto which all its other components are attached—known as the lower receiver for an AR-15 or the frame for a Glock-style handgun—is regulated as the gun. Make that one piece yourself at home, and you can buy the rest online in a few clicks, putting weapon components like barrels, slides, and triggers into your shopping cart without facing the slightest regulatory speed bump.

To test just how easy it was to build a ghost gun back in 2015, I made the lower receiver of an AR-15 three different ways: I 3D-printed it out of plastic; used a computer-controlled milling machine to carve one out of aluminum (or more accurately, to finish carving it, since I started with an 80 percent finished lower receiver, or “80 percent lower,” designed to almost—but not quite—meet the legal definition of that part); and even tried the more old-school technique of drilling out the same aluminum 80 percent lower with a manual drill press.

I was somewhat surprised at the time when a gunsmith I showed all three parts to warned me that my 3D-printed lower receiver wouldn’t be safe to build a rifle out of. He told me to instead stick with the milled aluminum one—which worked perfectly.

Flash forward to last December, however, and now it seemed a homemade plastic frame had been used in a carefully premeditated murder. When police arrested then 26-year-old Luigi Mangione in an Altoona, Pennsylvania, McDonald’s five days after he allegedly gunned down Brian Thompson, evidence photos of the gun found in his backpack showed a partially 3D-printed handgun with a printed silencer wrapped in hockey tape. I spoke to digital gunsmiths in the days after that revelation, and they identified the alleged murder weapon specifically as a variation on a printable, Glock-style frame known as the FMDA 19.2—an acronym for the libertarian slogan “Free men don’t ask”—released online by a gun-printing group called the Gatalog.

I hadn’t covered 3D-printed guns for years. But now that one had allegedly been used in Brian Thompson’s killing, I wanted to know: How far had the technology come over the past decade? And after 10 years of controversy surrounding these anarchic, lethal weapons, had American gun laws finally caught up with ghost guns?

I decided to find out by making a ghost gun of my own—again. And as soon as I began this quest, it became immediately apparent that the answer to the second of those questions was a resounding no. Creating a ghost gun with a 3D printer in America today is not only easier and more practical than ever—in most of the US, it also remains entirely legal.

In the decade since I built my first ghost gun, several states have passed laws that would now make that experiment a felony. In New York, it’s now illegal to make a gun without a serial number. In New Jersey, even sharing printable gun files is forbidden. In California, where I made my AR-15, it’s now against the law to so much as sell a 3D printer "used solely or primarily for manufacturing firearms.”

Yet at the federal level, the legal regime around ghost guns remains far patchier. In 2022, the Biden-era Bureau of Alcohol, Tobacco and Firearms (ATF) did ban “kits” designed to let anyone quickly make a ghost gun from the kind of 80 percent completed part I used in 2015. Gun advocates fought back, but the case was finally settled in March with a United States Supreme Court decision upholding the ban.

Despite that years-long legal battle, the ATF’s ban always applied only to components “readily convertible” into a gun. It says nothing about 3D-printed ghost gun frames fabricated out of thin air and spools of plastic filament.

All of that meant that the only real legal hurdle to my experiment in 3D printing a Glock-style ghost gun was a flight from New York to New Orleans, where a gun range on the east edge of the city had agreed to host me and my WIRED video colleagues as we built and test-fired the weapon. James Reeves, the owner of that range as well as a lawyer and gun-focused YouTuber, assured me that it would all be fully above board, so long as I was only making my ghost gun for my own use and not selling it or transferring it to anyone else. “It’s a free country down here in the great state of Louisiana,” Reeves said.

In fact, by removing an even easier way to circumvent gun control laws, the Supreme Court ruling on ghost gun kits may have only made 3D-printed guns more appealing, says Nick Suplina, a former prosecutor who now works as a gun control advocate at the nonprofit Everytown for Gun Safety. Between 2016 and 2022, 70,000 ghost guns were found at crime scenes, according to the ATF, many of them likely made from kits. Now that the kits have been banned, Suplina says, 3D printing may be the next best thing for those seeking to build a firearm without encountering any gun control laws.

“You now have this huge marketplace of people who really want untraceable, unserialized firearms with no questions asked,” Suplina says. “They're going to turn to 3D-printed guns and those that can supply them. 3D-printed guns are about to have their moment.”

By the time I got to Reeves’ gun range in Arabi, almost every component of my ghost gun was already there, thanks to the magic of ecommerce. The cost of the entire shopping spree totaled just $1,144.67 plus shipping—$200 for the slide, $35 for the barrel, $21 for the components of the trigger mechanism, and just $650 for a printer. For comparison, the 3D printer I’d used in 2015 had alone cost $2,900, or more than $3,900 in today’s dollars.

Every item on my list had been recommended by PSR, who had agreed to come to Arabi to walk me through the gun-printing process and had closely studied evidence photos of the gun allegedly found on Mangione to identify its components. The first evening in the workshop, after unboxing and setting up the printer, PSR showed me how to orient two digital FMDA 19.2 frames—downloaded in an instant from one of several online repositories of open-source gun models—in a desktop CAD application. The printer was fast enough that we would be able to print two frames in a single night, just in case I managed to screw up one during assembly.

I transferred the microSD card with the project file from my MacBook to the 3D printer, then hit the print button. The next morning, 13 and a half hours later, I walked into the garage to see that two eerily perfect black gun frames had materialized inside the machine’s glass front panel.

Now it was time to print the silencer. Legally speaking, this component of Mangione’s ghost gun was not like the others. Silencers, also known as suppressors, are illegal to make under the National Firearms Act of 1934 without a very particular gun-making license. For Mangione—and for me—printing a suppressor alone would have constituted a felony.

Conveniently, though, our host James Reeves did have exactly the sort of Federal Firearms License necessary to manufacture that precisely shaped tube. So we were careful to make sure that Reeves was the one who pushed print and pulled the black cylinder out of the printer three and a half hours later.

In the meantime, PSR sat with me as I built the rest of the gun. In contrast to the black mask and goggles that gave him the menacing look of a comic book villain, PSR was remarkably polite and forgiving as I clumsily attempted to follow his instructions. In total, a process that takes an experienced gunmaker around 20 minutes took me over an hour as I drilled out bits of stray plastic, hammered metal pins into the holes left behind, and fiddled with tiny interlocking metal and polymer pieces.

As a firearm took shape in front of us, I commented to PSR how strange it was that it’s only the frame of a Glock-style gun that’s regulated under American gun control laws and not the slide and the barrel sitting on the table in front of us—the very gun-like components that actually hold the round and contain the explosive forces that propel a bullet.

“That’s per the ATF,” PSR answered. “So, thanks, ATF.”

I asked PSR what appealed to him about 3D-printing guns. He started off with the hobbyist’s answer: That it lets him make “intricate, neat” gun designs that aren’t commercially available. (On his YouTube channel, for instance, he’s tested everything from the Orca—an AR-15 with as many printed components as technically possible, including its lower receiver, stock, grip, and even parts of its upper receiver—to a printable combined Glock-style gun and bong known as the “Glong.”) Even better, he argued, is that he can make these ever-evolving ghost guns with total anonymity and privacy.

But don’t 3D-printed ghost guns offer that same anonymity and privacy to actual dangerous people who might otherwise not be allowed to obtain a deadly weapon, even in America? “I don’t love that people commit crimes and kill each other with guns. But we live in a country that’s relatively free,” PSR responded. “Freedom is, ultimately, dangerous.”

By the next day, the silencer was done. After it finished printing, the plastic FTN suppressor—the acronym stands for “Fuck That Noise” or “Fuck the NFA,” in a reference to the National Firearms Act—still needed to be epoxied into a carbon-fiber tube for additional reinforcement. To comply with the NFA, Reeves’ team at the gun range had also registered it on a government website, added a serial number engraved on a washer at one end, and wrapped it in black hockey tape to match the one prosecutors say was found in Mangione’s backpack.

With that process complete, I threaded this doppelgänger silencer onto the muzzle of the pistol—a final step that suddenly made the gun look approximately twice as much like an actual DIY murder weapon—and took it into Reeves’ firing range for testing.

After a dozen years covering 3D-printed guns, I was about to test-fire a partially plastic firearm myself for the very first time. I’d watched enough videos of 3D-printed gun fails—barrels exploding, frames cracking—for this to actually make me sweat a little.

PSR had told me that any dangerous failure was unlikely, but that the most plausible risk to someone firing this kind of 3D-printed glock-style pistol would be that, if the frame failed, the gun’s recoil might send the slide flying off backwards into their face. So for the first shot, I decided to hold the gun out to the side and fire it from the hip.

I gripped the ghost gun, pointed it vaguely at the human-shaped paper target downrange, and squeezed the trigger. Bang. The sudden sound of the explosion filled the range, even with the suppressor on. I was surprised to see a hole in the target’s torso, not far from its dead center.

For that first tentative test shot, we had loaded only one round into the magazine. Now I added a few more, brought the gun up to eye level—briefly wondering, as I did, whether I was about to get a chunk of steel to the face—and fired again.

The next shot put a hole even closer to the center of the target, now that I was actually sighting it. But I could immediately see that, exactly as in the closed-circuit footage of Brian Thompson’s killing, the gun hadn’t fully “cycled”: Instead of the slide loading a new round into the chamber and then returning to its original position, as it should in a semi-automatic weapon, I had to “rack” the gun—pulling back the slide manually—to eject the round’s casing and then give it a bump with my fist to push it back into place for the next shot.

I squeezed the trigger again. Click. It had misfired. I racked the gun again, gave it another punch in the back of the slide with my left hand, fired again, and heard the click of another misfire.

PSR took the gun, tried a few shots himself and got a similar mix of bangs and clicks as the gun misfired repeatedly. For the next half hour or so, he troubleshooted it, apologizing as if he felt personally responsible for the ghost gun’s shortcomings. He removed the suppressor, lubricated the slide, swapped in different ammunition, and even briefly changed the barrel for a higher quality one.

Ultimately PSR came to the conclusion that the problem was the relatively cheap slide he’d recommended based on trying to match the one in prosecutors’ evidence photos. None of these issues, in other words, had anything to do with the 3D-printed frame.

PSR spent a few minutes smoothing down an internal surface of the slide with a file, reassembled the gun, and we took turns firing it again, now with the suppressor off to isolate the issue. After a few more shots, PSR was barely nudging the slide to get it back into place—then, as it wore in, not touching it at all between pulls of the trigger. Finally, he unloaded an entire magazine into the target in just a few seconds. “There it is!” he yelled between shots. “There we go!”

When the gun was empty, he turned to me with a thumbs-up. “We have a functioning, 3D-printed semi-automatic Glock-style pistol here.”

I screwed the silencer back into place and fired it again. Now the gun acted precisely like the one from the CCTV video of Thompson’s murder: It still didn’t quite cycle, and I had to rack it and tap the back of the slide with every shot. That was likely because, just as with the gun allegedly found on Mangione, the silencer was still preventing the slide from achieving its full range of motion. In fact, watching the surveillance video again, I could now see that there was no hesitation in the shooter’s racking and tapping of the gun—that he was fully prepared to manually cycle it, just as I was doing. I now understood that he had likely practiced at a range just as we were doing and perhaps had even troubleshooted his weapon in exactly the same way we had.

I fired the gun six more times before it misfired again. On that final, seventh shot, it failed in a new way: A live round actually appeared to have lodged itself into the barrel. It would take some precise surgery to get it out safely. Testing was over.

Despite the gun’s eventual failure, our experiment in building an uncontrollable, lethal weapon had been a success—it had fired more than 50 times in total.

Over the previous half-dozen shots, meanwhile, as the ghost gun replicated precisely the performance of the one in the surveillance video, I had come to a disturbing realization: that I was now experiencing exactly the sensations—the same exact repetitive squeeze of the trigger, recoil, racking and tapping of the slide—that a murderer had felt as he gunned a man down on a Manhattan sidewalk.

Late that night, I turned in my two ghost gun frames to a police station in New Orleans’ French Quarter. After all, they were mine, and I couldn’t legally transfer them to anyone else or fly with them back to New York, where they’re illegal.

When I’d similarly turned over my AR-15 ghost gun lower receivers in 2015, the cops had wordlessly accepted the components without making eye contact, as if I were an insane person. This time, when I explained to the police why I was handing over plastic gun parts, they looked them over curiously and asked me a few questions—but already knew exactly what a ghost gun was.

I wondered what their reaction would be in another 10 years. By then, perhaps, partially and even fully 3D-printed ghost guns will be commonplace. America’s gun control system, after all, has shown no sign of keeping up with the pace of DIY firearm technology. Unless that changes, it’s safe to expect a future with more ghost guns than ever, and more people—like a certain alleged CEO killer—ready to use them.