3D Printed Gun Myths – Legality, Parts, Blueprints, & Materials 

3D Printed Gun Myths

Legality, Blueprints, & Materials

In the debate over 3D printed guns, technical context is often rare, and we’re hoping to clear up some misconceptions. Easy, simple, accessible: 3D printing is that “new, simple thing”, that’s not very new and not very simple. While most people are well aware of the things 3D printers can do, most are not aware of what they cannot do

The term “3D printed gun” is often misunderstood. 100% thermoplastic guns have yet to be a fruitful technique for manufacturing firearms. Before addressing legality, the differences in 3D printed firearm design, components,

Myth: The Debate Over 3D Printing Firearms is New

The first 3D printed gun made headlines in 2012 when 24-year-old 3D printing enthusiast, Cody Wilson, indicated his intent to manufacture and distribute weapons using a Stratasys 3D printer. Stratasys, a self-proclaimed world-leader in 3D printing, promptly canceled Wilson’s $20,000 U-Print-SE and retrieved the printer— the machine was never removed from the box.

Cody Wilson, founder of gun manufacturing advocacy group of Defense Distributed, arguably violated federal firearm laws before ever getting off the ground. He was also not an engineer. 

In the case of Defense Distributed’s Liberator, a 3D printer renders almost every component in plastics….the handle design sometimes includes a metal weigh in the grip and also a metal firing pin. The end user could choose to forgo metal components completely, but, they would be in violation of federal firearms laws.

The manufacture and sale of a firearm requires a federal firearms license. But what about selling the blueprints for firearms? 

Wilson’s first working 3D printed firearm prototype was a small, single-shot pistol materialized from ABS thermoplastics. The plastic parts required a 48 hour build time (time in the printer) before hand assembly. then required hand assembly. 

If it didn’t blow up on the first round, the pistol fired with a lifespan of just 10 – 20 shots. 

The first Liberator gained Wilson notoriety after publishing a 3D print-ready file (STL) which online enthusiasts could materialize from their own 3D printer.

Media and regulators largely disregarded that the pistol requires a metal firing pin and hand reloading after every shot. 

How Does the ATF Define a Gun?

The term “firearm” is defined by 18 U.S. Code § 921:

(A) any weapon (including a starter gun) which will be or is designed to or may readily be converted to expel a projectile by the action of an explosive;

(B) the frame or receiver of any such weapon;

(C) any firearm muffler or firearm silencer; or

(D) any destructive device. Such term does not include an antique firearm.

In the case of Defense Distributed’s Liberator, the handle design included a metal weight and metal firing pin. The ATF prevents the manufacturing of any firearm that forgoes metallic parts.

Myth: Assembling a 3D printed gun of 100% plastic is already illegal.

“The law prohibits a person from assembling a non–sporting semi-automatic rifle or shotgun from 10 or more imported parts, as well as firearms that cannot be detected by metal detectors or x–ray machines.”


The single-shot pistol rarely fired, required hand reloading, and frequently exploded. The “Liberatory” failed every standard of manufacturing, firearms, and engineering, but also — basic common sense. When printed and tested by ATF agents, the Liberator exploded without ever firing a shot

If I ever get in a shootout, please let my opponent have a 3D printed pistol. 

This story should end here. But it turns out Wilson’s critics may have underestimated the man — and overestimated the technology. Wilson didn’t have engineering prowess. But he understood how to garner support from the counterculture and fuel media spins

Eventually regulators starting taking notice.

In August 2018 a district court judge extended a ban on web distribution of blueprints for 3D printed lower receivers for semi-automatic rifles and pistols.

In response, announced he’d sell his blueprints as physical deliverables instead of uploading them online for download. In permitted states, you’ll just pay a $7 shipping fee.

Myth: 3D Printers Legally Create Guns that Cannot Be Detected with Metal Detectors and X-Ray Machines

The term “3D printed gun” is often misunderstood. 100% thermoplastic guns have yet to be a fruitful manufacturing technique for reasons disclosed later in the post. Before addressing legality, the differences in 3D printed firearm design, components, and assembly methods must be distinguished.

Methods of Manufacturing a 3D Printed Firearm

Method 1

The first method produces a 3D printed component that mimics traditional metal lower receivers for connection of metal assemblies, trigger frames, and barrels. After printing the lower receiver, aftermarket barrels, stocks, and upper receivers are sourced from 3rd parties without serials numbers or registration requirements. This is a common and controversial workaround to avoid ATF firearm regulations. Retail-ready, fully assembled firearms must contain a serial number for identification and registration.

Method 2

The second technique includes printing every component of the weapon, including the springs, barrel, and grip assembly with a 3D printer.

Myth: Cheap, Accessible Filaments Are Great for 3D Printing Robust Parts

What’s the problem with using thermoplastics for 3D printed guns?

They Melt.

By definition, a thermoplastic becomes molten plastic when heated and hardens upon cooling. Nozzle based (extrusion) 3D printers are known for effective tensile strength, low cost per print, and are easily adapted for assembly and limited end-use applications. The technology is known as Fused Filament Fabrication (FFF) and equatable to Fused Deposition Modeling (FDM – a patented trademark of Stratasys systems).

Theoretically, there are handful of 3D printing filaments capable of withstanding the rapid expansion, heat, friction, and high pressure gasses produced by small munitions. Any tactical weapon must resist moisture, impact, overheating, dirt, and UV exposure. 90% of 3D printing materials don’t meet these basic requirements.

Common Flaws of ABS Plastics for 3D Printing

ABS plastics are the most common and accessible thermoplastics used in 3D printers. If there’s one thing introductory 3D printing filament materials were not made for, manufacturing firearms might be at the top of the list.

Like most people, Cody Wilson isn’t an engineer. With a melting point of 222 F°, ABS is typically extruded at a temperature is between 204 – 238 °C (400 – 460 °F). When heat is reapplied, the material will return to a molten form.

Unfortunately, gunpowder burns at ~5,000 °F and even advanced gun barrel designed for rapid heat dissipation may reach several hundred degrees at a high rate of fire.

ABS is not meant to withstand prolonged heat under duress. The weakest assembly points will quickly fault. At best, the firing pin unseats from the assembly and the gun will refuse to fire. At worst, it implodes.

While ABS plastics are cheap and more durable than other popular novice materials like PLA, they have very poor resistance to UV light. Performance and mechanical properties degrade quickly when exposed to sunlight.

Limitations of ABS 3D Printers

ABS requires a heated printed bed and enclosed chamber. Heated print beds and enclosed chambers require significantly larger upfront costs ($800 – $3,500) than open-faced designs.

Unlike ABS or PLA materials common among hobbyists, commercial-grade 3D printing filaments render prints that are durable and thermally stable for more robust applications. Novel materials allow processes like drilling and snap fitments for multi-part assembly with less vulnerability to heat, moisture, friction, and repeated action.

Filaments range in capability (and price) between consumer grade plastics like ABS or PLA, and engineering or aerospace quality materials like PEI (polyetherimide), Nylon, polycarbonate, and carbon composites.

Myth: High-Temperature Thermoplastics are Readily Available

A printer capable of high-performance thermoplastics ranges between $5k – $500k on the retail market.

Thermoplastics capable of melting points upwards of 7000 °F exist, they have yet to be adopted for 3D printing. High-temperature materials are trickling into open source markets, but the application has yet to reach consumer-grade printers.

Myth: 3D Printers Bring Guns to Market Faster

The print rate is a key performance benchmark of a 3D printer. Once something goes wrong during the 3D printing process, it goes really wrong. Any small glitch such as filament not feeding properly, a design flaw, or a muddy extrusion rate skews filament placement, cooling rate, and nozzle trajectory. A botched print must be started over from scratch, which usually means an extra 24 – 72+ hours of uninterrupted build time.

But What About 3D Printed Metals?

3D printed metals are notoriously hard to print, expensive, and not easy to work with.

3D printed metals may be relevant in the near-sometime-later future of technology, but likely a decade away from consumer accessibility.

Myth: 3D Printing is The Best Way to Obtain an Untraceable Firearm

Modern firearm designs such as the AR-15 semi-automatic assault rifle have hot-swappable modules that are sourced piece-by-piece and then assembled into a completed weapon post-delivery.

As opposed to 3D printing an entire weapon, Wilson focused his efforts on printing “lower receivers” which provide a housing for the firing pin and trigger mainframe. Barrels, stocks, clips, and optics are then ordered a la carte to meet the user’s needs without requiring serial numbers or ownership permits.

The lower unit is the only component of a weapon that differentiates an object between a paperweight and a firearm. Before the lower unit is deemed as a firearm, it requires an individual to make custom alterations for fitment of the trigger and chamber assembly.

Myth: Ghosts Gun are Illegal

80% receivers provide a prefabricated lower that requires slight modification and are openly sold online. The aluminum mainframe requires some precision tooling with a drill press to connect a trigger assembly and mechanize an action of firing.

Manufacturing a weapon for personal use (non-felons) is not illegal in many states. In many cases, a weapon built for personal use does not require a serial number or registration (again, varies state by state). These are commonly referred to as “ghost guns”.

In states with most strict legal parameters, once a receiver is drilled and slotted for assembly it is considered a firearm, and therefore subject to state and federal regulation.

In the most simple terms, a ghost gun is a firearm without serial numbers. Ghost guns do not require background checks or registration, however, they must be manufactured by the individual and not assembled from an already completed receiver or frame.

Each state has its own limitations on the types of weapons permitted for self-manufacture, and stipulate their own regulations for registering homemade firearms.

Myth: 3D Printing a Safe & Functional Firearm is Easy

A July 2018 chronicle in the L.A. Times demonstrates that for organized criminals, tried and true metal lower units are the most direct path to military-grade assault rifles.

Digital modeling, print optimization, iterative design, post-processing, and material efficiency are all essential for successful, scalable prints when extruding molten thermoplastics.

Those less familiar may think 3D printed parts pop off a print tray like a soda can falling out of vending machines. Unlevel print beds, saturated or stuck filaments, clogged extruders, or too slow/fast feed are a short list of reasons 3D printed builds fail.

Fused Filament Vulnerabilities

Fused filament designs sometimes require significant post-processing to remove support material, smooth edges, and remedy blemishes. Final fit and form require precise measurement and significant elbow grease. Build time is slow, and the final product is subject to many more variables with far less reliability and durability than traditional manufacturing methods. These are among reasons firearms manufacturers reserve 3D printing technology for prototyping accessories, ergonomics, and proof-of-concept.

Related: Why Do My Builds Keep Failing – Is Moisture a Silent Killer of 3D Printed Parts?

Because some 3D printing filaments are hygroscopic, meaning that they absorb moisture from the air, prolonged exposure to even moderately humid room air causes moisture saturation. After 150 hours in standard conditions, PLA filament may swell up to 40 micrometers before reaching its saturation point. 3D printers rely on tight tolerances and extremely small layer heights. Before the print even gets underway, an increased filament diameter of even 20 – 40 microns, (roughly the width of a human hair) can derail a build before it ever begins.

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Myth: Regulation Can Stop Web Distribution of 3D Printing Blueprints

Since the rise of the internet, digital sleuths have found ways to build illicit markets in the dark corners of the web. The internet allows anonymous exchange of three major resources: currency, files, and communication.

The “darknet” was marked with infamy after the arrest of Ross Ulbricht, founder of the Silk Road. The Silk Road was an online black market that facilitated money laundering, computer hacking, narcotics trafficking, fraudulent document trafficking, and alleged murder-for-hire.

Encrypted transactions were crucial for the Silk Road market which produced upwards of 100 million in yearly revenue. These transactions were facilitated with BitCoin. BitCoin, is an encrypted digital currency (cryptocurrency), which shields personal identity but passes artifacts of ownership anonymously through a network of computers. Payments are arguably secure and extremely difficult to trace. Much like an offshore bank account, asset ownership is maintained and liquid, but the owner of those assets remain unknown.

Privacy-forward internet browsers such as TorBrowser and file-sharing networks like BitTorrent allow deep harbors for criminal activity, but they also represent the frontline of technology against identity theft, ensure transaction integrity, and protect personal web data.

Sometimes, the late-evolving benefits of new technology are only realized when bad actors arise from the shadows.

So What? How Do TorBrowser and Cryptocurrency Relate to 3D Printing Blueprints?

Yes, government policy may prevent Cody Wilson from openly distributing blueprints for a 3D printed firearm through public channels. It has not stopped him from doing so through private channels.

Although we won’t provide a link to them here, a simple Google search will reveal dozens of reuploaded files via GitHub sourced from Defense Distributed’s Liberator project. For $40 a year, a dedicated VPN network allows a user to upload and share files anonymously within peer-to-peer (P2P) networks. Large-scale distributors could simply “leak” their 3D printing download files without discourse.

The attempt to remove 3D printed components from open markets will follow historical precedent — when high demand meets regulatory injunction, black markets thrive. Instead of residing in observable communities scattered across public domains, the dark web will congregate in dark places — the savvy — and the savage.

Much to the chagrin of the public , stopping private users from trading illicit files over forums and online program hubs is extremely challenging. The existence of the Silk Road is just one example. Is it a brilliant success gone bad, or a cold future for the distribution of proprietary materials through web mediums?

Creating Technical Context for 3D Printed Guns

It’s been over 5 years since 3D printed guns first broke headlines. The landscape and concern over 3D printed guns continues to boil over — 3D printing capabilities have yet to reach a fever pitch.

Systems, material capabilities, print process, preliminary engineering, post-processing, environmental factors— little consideration is needed when 3D printing trinkets and spare lawn mower parts. Meanwhile, 3D printing a weapon capable of firing a projectile down range is more challenging — it’s also a lot more dangerous.

Engineer or Enthusiast? What impact do you think 3D printing will have on the future?