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Weapons Expert Adam Firestone on The Reality of 3-D Printed Firearms

Special thanks to RU’s resident expert ADAM FIRESTONE [1] for addressing the topic of 3-D printed firearms. I’ve been curious about these ever since I first heard about them. My imagination went wild, coming up with all kinds of ideas for wrongdoing – fictional, of course. As always, Adam was able to set me straight.

LineOfFireGun [2]

In the 1993 suspense/crime thriller In the Line of Fire, Clint Eastwood plays an American Secret Service Special Agent named Frank Horrigan and John Malkovitch is CIA assassin gone bad Mitch Leary. Leary is bent on killing both the President and Horrigan. To this end, Leary prepares for the assassination by building a two-barreled pistol made from a composite, plastic-like material which can evade detection by magnetometer. Interestingly, the composite gun is used several times in the film without breaking, and, after filming was complete, was destroyed in a legally compliant manner by being cut into three pieces.

LineOfFireGunCutUp [3]

Concern and fascination with easily hidden, hard to detect, “plastic” guns predates In the Line of Fire by a number of years. When Glock pistols were introduced into the US commercial market in 1985, misunderstanding and technical confusion led to wildly inaccurate claims that the guns, with their polymer frames, were thinly veiled assassin’s tools.

GLOCK 17 [4]

In fact, 83% (by weight) of the Glock is ordinary gun steel and the “plastic” parts are a dense polymer which is radio opaque and thus also shows up under X-ray security equipment – such as the backscatter X-ray machines used at American airports. In addition, virtually all of the Glock’s “plastic” parts contain embedded steel components. This is not done to make the pistol “detectable,” but rather to make the polymer parts functional. For example, the Glock’s slide rides on four steel rails that are integral to the polymer frame. Without those rails, the slide would simply fall off! Additionally, neither Glock, nor any other gun maker has ever produced a “ceramic” or “plastic” firearm which is undetectable by ordinary security screening devices.

Worries about plastic, ceramic and other types of “undetectable” pistols had largely returned to the province of fiction writers (and intelligence agencies) when the tocsin was again sounded with the advent of 3-D printers. 3-D printing (or “additive manufacturing”) is one of any number of processes that produce a three-dimensional solid object of almost any shape from a digital model. 3D printing is achieved using an additive process, in which successive layers of material are laid down in different shapes. This makes 3-D printing, as a manufacturing process, very different from traditional machining techniques which rely on the removal of material by methods such as cutting, milling or drilling (“subtractive manufacturing”).

World War II Liberator Pistol [5]

World War II Liberator Pistol

The 3-D printer itself is really a limited type of industrial robot that carries out an additive process under computer control. 3-D printing technology has been available since the 1980s, but it was not until the early 2010s that the printers became widely available commercially. Since the turn of the century, 3-D printers have become much more prolific, and prices have dropped significantly. Despite the price drop, the overall market for 3-D printing technology has only increased. Indeed, between 2011 and 2012, the value of 3-D printers and services grew 29%.

Liberator, 3-D Printed [6]

Liberator, 3-D Printed

Accompanying the rapid proliferation of 3-D printing technology were rising fears that the capability would be used for the illegal and uncontrollable production of firearms. Indeed, in May 2013, Cody Wilson, then 25 years old, made history when he test fired the first pistol printed on a 3-D printer. The pistol was named the “Liberator” in honor of a stamped, sheet metal, single-shot firearm produced during World War Two to arm resistance fighters.

Wilson’s gun was made of plastic, with the exception of two metal pieces: a metal firing pin and a six ounce piece of steel that is required by law under the Undetectable Firearms Act. 15 of the gun’s 16 functional pieces were printed by a Stratasys Dimension SST 3D printer (the metal firing pin is the 16th piece). While the Liberator functioned as advertised, it was little more than a proof of concept. It was slow to load. Due to its unrifled barrel it was extremely inaccurate and it had a limited lifespan; there were only so many times that the plastic was going to stand up to the pressures and stresses of firing modern ammunition.

Defense Distributed AR-15 with 3-D Printer Lower [7]

Defense Distributed AR-15 with 3-D Printer Lower

Much more interesting, and practical, was the use of 3-D printers to produce AR-15 lower receivers. On the AR-15 rifle, the lower receiver bears none of the firing stresses – those are borne by the steel bolt and barrel extension. The lower receiver, in contrast, serves only to be a housing for the magazine and fire control components and an attachment point for the buttstock and pistol grip. Under US law, however, it is the only controlled part of the rifle, and commercial production and sale of AR-15 lower receivers requires licensure from the Bureau of Alcohol, Tobacco, Firearms and Explosives (BATFE).

HaveBlue AR-15 Lower Receiver [8]

HaveBlue AR-15 Lower Receiver

In 2011, a shade-tree gunsmith, using the Internet nom de plume of HaveBlue announced in online forums that he had successfully printed a serviceable .22 caliber pistol. The pistol worked, firing over 200 rounds in testing. HaveBlue then decided to use his printer to make an AR-15 rifle. To do this, he downloaded plans for an AR-15 receiver in the Solidworks file format from a site called CNCGunsmith.com. After some small modifications to the design, he fed about $30.00 of ABS plastic feedstock into his late-model Stratasys printer. The result was a functional AR-15 lower receiver. This was mated to legally available parts. And, despite some minor feeding and extraction problems, it worked.

HaveBlue also tested the “marketplace” for 3-D printed firearms. To do this he asked Thingiverse.com, a 3-D design sharing site run by Makerbot Industries, whether it was permissible to post weapons designs or not. According to HaveBlue, Makerbot’s senior leadership decided to not disallow, but to discourage, the posting of weapons designs. Haveblue then posted a design for an AR-15 lower receiver on Thingiverse. The design stayed online for a while – and nobody is certain how many times it was downloaded and/or redistributed – but eventually, Thingiverse removed the file.

What’s clear from all of this is that it’s perfectly feasible to make firearm components at home using 3-D printers and commonly available materials. What’s less clear is whether we should care, or how effective a plot device this would be.

To start muddying the waters, there’s absolutely nothing illegal about manufacturing a firearm for one’s own personal use, provided it is not being made for resale. According to the BATFE, firearms may be lawfully made by persons who do not hold a manufacturer’s license under the Gun Control Act of 1968 (as amended) provided they are not for sale or distribution and the maker is not prohibited from receiving or possessing firearms.

The only time “permission” is required is if the firearm being manufactured possesses a barrel below the minimum statutory length (18” for shotguns, 16” for rifles). In that case, the firearm falls under the provisions of the National Firearms Act of 1934, and requires a tax payment and advance approval by the BATFE. The only real restriction is on the production of a machinegun, or fully automatic firearm, which can only be made for the official use of a Federal, State, or local government agency.

Next, claims that 3-D printing will create a huge pool of untraceable black market firearms simply fail to take into account the reality of the production effort and the nature of the illegal firearms market. To 3-D print a receiver, and then produce a serviceable firearm requires a non-trivial investment in the printer, a computer and raw materials. It also requires a stock, if one is producing an AR-15, for example, of AR-15 parts.
It also requires significant technical knowledge in terms of both 3-D printing and gunsmithing. After all, one has to master both the 3-D printing process and the subsequent assembly. At the same time, there is a sizable trade in illegal firearms.

Now put yourself in the position of a criminal or terrorist. Why bother going to all the time, effort and expense associated with printing and assembling a 3-D firearm that MIGHT work when you can simply buy one illegally? In the end, it’s simply more trouble than it’s worth to print a firearm for nefarious purposes.

Unless, of course, you’re John Malkovich.


Do you have questions for Adam about 3-D printed firearms? Please comment below if you have an idea for a future topic for Adam.

Check back next week when Christine Pride reveals editor’s secrets and Nancy Fraser discusses writing cross-genre!


Bio: Adam Firestone brings more than 25 years of experience with weapon systems including small arms, artillery, armor, area denial systems and precision guided munitions to Romance University. Additionally, Adam is an accomplished small arms instructor, editor, literary consultant and co-author of a recently published work on the production of rifles in the United States for Allied forces during the First World War.

Adam has been providing general and technical editing services to authors and publishing houses specializing in firearms books since the early 2000s. Additionally, Adam provides literary consulting services to fiction authors including action scene choreography, technical vetting and technical editing. In this line of experience, Adam has had the fortune to work with well known authors including Shannon McKenna and Elizabeth Jennings.

Check out Adam’s blog here: http://adamfirestoneconsultant.blogspot.com/ [9]

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9 Comments To "Weapons Expert Adam Firestone on The Reality of 3-D Printed Firearms"

#1 Comment By Carrie Spencer On January 31, 2014 @ 9:09 am

Morning Adam!

I saw a show on 3D printing…the made a wrench – granted it was a BIG wrench – and it took well over 3 hours. It worked, the adjustable mechanism on it worked as well, but it seemed a long time to wait….

otoh, if I were a lunatic assassin, I’d have all sorts of free time on my hands, right? =) i agree, it would be much easier to buy one illegally, but not nearly as much fun to write in a book.

Thanks for posting with us Adam!


I guess I would worry most about the gun mis-firing and killing ME instead of my target. Or the barrel melting or any number of things that can go wrong with a regular gun, much less one I’d manufactured in my basement. =)

#2 Comment By Adam Firestone On January 31, 2014 @ 5:24 pm

Hi Carrie,

The issue that you’re rightly worried about is what happens when materials never intended to bear the pressures of modern ammunition are put to that use.

The results aren’t pretty, and they aren’t limited to plastic. About thirteen years ago, a company called Williams Arms Company in Sisters, Oregon, produced an aluminum receiver for the FAL rifle.

It was beautifully made…and failed catastrophically when subjected to the 50,000 PSI of pressure attendant to firing a 7.62mm NATO round.

The issue is generally as much in materials – not in manufacture. Interestingly, 3-D printed guns made of sintered metal have fared reasonably well.

Hope this helps,


#3 Comment By Becke Martin Davis On January 31, 2014 @ 9:10 am

Adam – I don’t remember where I first heard of 3-D printed firearms (or 3-D printed ANYTHING, for that matter) but I’ve been intrigued by the idea every since. Thanks for shedding light on the process and for explaining the ins and outs of plastic/ceramic firearms. You are the Answer Man!!

#4 Comment By Adam Firestone On January 31, 2014 @ 5:25 pm

Hi Becke!

I hope you find the info useful!!

All the best,


#5 Comment By Jennifer Tanner On January 31, 2014 @ 4:43 pm

Hi Adam,

I heard about 3-D printed firearms in the news, but had no idea what they were, but I do remember the scene where Malkovich’s character shoots the two fisherman with his plastic gun. Thanks for another informative post!

#6 Comment By Adam Firestone On January 31, 2014 @ 5:25 pm

Hi Jen,

Happy to help!!

All the best,


#7 Comment By Becke Martin Davis On January 31, 2014 @ 9:01 pm

Adam – Thanks so much for joining us today! I hadn’t considered some of the problems with 3-D printed firearms, I just thought it might be cool to include them in a story. If I did that now, I’d want to incorporate the disastrous problems you mentioned here. Thanks for the ideas! 😉

#8 Comment By Carrie Spencer On February 1, 2014 @ 12:41 am

Those disastrous problems would work awesomely for offing your villain. =) just saying..lol

#9 Comment By Rosario O. Lamb On February 14, 2014 @ 1:37 am

Just to clarify/summarize, the recent articles about 3d printing and firearms have nothing to do with producing WORKING firearms (only non-critical parts). They have nothing to do with automatic weapons. Any finally, this is not a new capability. It’s just letting lazy people do it.