Luigi Mangione Reportedly Used 3D Printed Ghost Gun to Kill UnitedHealthcare CEO Brian Thompson

Luigi Mangione has been arrested on weapons charges and is believed to be the suspect in the assassination of UnitedHealthcare CEO Brian Thomson. It is now widely reported that the suspect had a 3D printed weapon and silencer on him. Arrested at a McDonald’s after being recognized by a patron, Ivy League-educated Mangione seems to be a Ted Kaczynski-inspired anti-corporate former software developer. The assassination appears to be motivated by misgivings about capitalism in general and the U.S. healthcare and corporate systems in particular.

This case has already raised eyebrows at the sheer amount of sympathy garnered by the assassin for opposing the U.S. healthcare system. The news has dominated social media at a time when five decades of the Assad regime have been swept away, and conflict is ongoing in Ukraine and Israel. At the center of the case may lie a 3D printed gun. As we speculated in a previous article:

“The assassin’s calm, practiced handling of the cycling issue—executed almost seamlessly—suggests extensive preparation and familiarity with this problem. Most individuals would hesitate or require more time to clear a jam, but this individual appeared prepared for the malfunction.

“The most plausible explanation is that the suppressor was homemade and reduced the weapon’s pressure to such an extent that cycling the round became unreliable, necessitating extensive practice to ensure functionality. The use of subsonic ammunition, while reducing noise further, could exacerbate this issue by making the system even more prone to malfunctions. Anticipating such malfunctions and training to address them swiftly aligns with the methodical execution observed, underscoring the likelihood of an improvised suppressor created with desktop 3D printing (or another home brew method)…..Homebuilt suppressors can be constructed through various methods, and 3D printing is one of them. However, if the weapon itself was also manufactured at home, the likelihood of 3D printing playing a role increases, particularly for components such as the lower receiver or other parts of the firearm…..Ghost guns have often captured media attention, with 3D-printed firearms frequently linked to criminal activity. If 3D printing becomes a significant aspect of this case, it could reignite concerns and lead to renewed legislative focus on 3D-printed weapons. Historically, laws have been enacted to ban the production of 3D-printed guns or the distribution of associated files. This case could add momentum to such efforts, potentially affecting printer manufacturers and file-sharing platforms alike. In either scenario, the industry risks being cast in a negative light.”

Normally, gas escapes easily from a gun when a round is fired. Adding a suppressor to a gun increases back pressure, preventing all the gas from being expelled as it once was and forcing some back into the gun. Professionally 3D-printed suppressors typically mitigate this pressure, but suppressors can also cause weapons to gunk up faster. Additionally, pistols that rely on recoil mechanisms may become harder to cycle.

If the round is subsonic—either due to design, modifications, or effects of the suppressor—the sound is mitigated, but cycling issues may become more frequent. Pistols often use blowback or recoil-powered systems. In blowback pistols, a well-balanced spring assembly opens at the right time to expel the cartridge after the round leaves the barrel. Any disruption, such as lack of lubrication, part misalignment, or altered pressure, can upset this balance and cause cycling issues.

Short recoil systems, a common gun architecture, require the barrel to move in lockstep. A suppressor’s added weight or other factors can disrupt this movement. Guns using Browning or tilting-barrel designs often require a Nielsen device (also known as a muzzle booster, LID, or piston). This device includes a spring that captures escaping gas to ensure the barrel completes its movement.

In contrast, designs like the Welrod—a single-shot bolt-action weapon—require manual cycling for each round, bypassing suppressor-related cycling issues. The variety of firearm designs and the effects of suppressors can make their impact complex and confusing for users.

The Welrod pistol design appears to have been the basis for the 3D-printed weapon. However, several weapons experts expressed doubt about this for a few reasons. They noted that a genuine Welrod would cycle the round correctly, and its operation would differ from what was observed. Furthermore, acquiring a Welrod or variant legally requires a National Firearms Act stamp. The same is true for suppressors. The associated paperwork creates a significant paper trail, and the rarity and traceability of such a pistol would make it highly likely for law enforcement to catch a criminal using one.

On the other hand, a less reliable 3D-printed firearm might share the Welrod’s bolt-action design while exhibiting cycling issues, as seen in the video of the shooter. Alternatively, it could be a modified version of the Welrod, retaining its appearance but functioning differently. A 3D-printed variant would visually resemble the original but could cause confusion for police investigating the case, leading them to search for factory-made Welrod pistols and variants. Slight modifications to the Welrod’s operation might also mislead even seasoned gun experts.

At the time of the arrest, an officer reported finding “a black 3D-printed pistol and a black silencer,” which raises questions because the Welrod design integrates the suppressor directly into the pistol. This has led to some confusion, compounded by conflicting reports: some sources assert that both the gun and the silencer were 3D printed, while others specify that only the gun was 3D printed.

Adding to the uncertainty, NYPD Chief of Detectives Joseph Kenny has stated “that the gun appears to be a ghost gun, may have been made on a 3D printer, with the capability of firing a 9mm round.”

As noted in our previous article, 3D-printed Welrod pistol files are available online. During my research for these articles, I encountered multiple versions of Welrod pistol designs. To avoid amplifying access, I will refrain from linking specific sources. However, it’s important to note that assembly guides for the Welrod and its variants are widely distributed on the internet. These files can be found on file-sharing platforms and gun enthusiast websites.

Similar designs and comparable pistols operate in much the same way, with forums discussing details like trigger weight, components, and operational tips. These communities often engage in heated debates about materials to use or the durability of barrels, measured in the number of rounds they can handle. Members frequently share safety reminders, such as wearing protective glasses, and discuss cost-effective methods for constructing weapons. Many individuals are using Ender 3 printers and PLA filament to create these firearms.

These online communities collaborate on various designs, constantly iterating and refining them. As I’ve emphasized before, it’s critical for the industry to adopt a clear stance on these developments.

What are we, as an industry and a community, responsible for when it comes to 3D-printed weapons? Do we take active measures to discourage their creation and distribution, or do we consider this issue beyond our purview? Are we prepared to address this proactively, or will we wait until restrictive legislation forces our hand and complicates our work?

A few years ago, the inefficiency and unreliability of 3D-printed guns made them a less viable option compared to legally or illegally acquired firearms in countries like the United States. However, the emergence of silenced variants changes the equation, particularly for those with malicious intent. These weapons offer several advantages for assassins: lack of traceability, ease of disposal, and quiet operation. This shift marks a troubling evolution in the technology’s misuse.

Given the intense scrutiny and media coverage surrounding this case, it seems only a matter of time before another individual commits a similar act using a 3D-printed weapon. Previously, one could argue that a firearm made with a lathe or CNC machine would outperform a 3D-printed gun in terms of reliability and firepower. But now, if the sole purpose is to kill an unarmed person, a 3D-printed gun might suffice.