I Weaponized my 3D Printer / by Alex Schreer

Its taken me a few weeks of thought on whether to share this on the blog, it can easily be perceived as political in nature without the proper context. The following post is not meant to take sides on the argument it was simply an experiment to gain a deeper understanding about a topic, so that I could come to my own personal stance on the topic.

"The greater our knowledge increases the more of our ignorance unfolds " - JFK

There is no question that the accessibility to 3D printing has forever altered the way we can create objects. The capacity to model and then manufacture anything in the comfort of your own home is step in a positive direction for humanity as a whole. With it passing year this technology gets better, cheaper, and more capable of doing large scale production, the best example being Adidas working with Carbon 3D to release the world first consumer scale 3D printed shoe sole. 

With this amazing power to create, it is understandable that eventually it would be used to create weapons, the main focus of concern amongst news media being "Guns". A re-occuring company that found itself at the center of this media storm was Defense Distributed, an open source company that designs and releases weapons online to be downloaded and 3D printed. They were the first group to design and make a fully 3D printed, single shot 9mm pistol a feat that took years of development. But thats not where their infamy stems from, it finds its roots in their AR-15 lower receiver, that could be purchased on their website and printed at home. If you are curious in knowing more about them the Vice documentary linked below does a great job of explaining it in more depth. 

Over time I'd become fascinated with this topic, for once it a small channel of innovation in an industry that's core designs haven't been changed in centuries. Also its a topic that raises many questions about the accessibility of guns in America, I found myself coming back to the question "is it really that easy to just print one of these things and go shoot it?". I had to know for myself, after watching news specials that had made it seem like I would start my printer, and wake up the next morning to a fully functionally assault rifle with no trace of its origin. 

It took me a few months to get the 3D file for the AR-15 lower from Defense Distributed, after its initial release it fell under heavy scrutiny and due to pressure from the ATF they had to remove the file from their site. However by that time it had been downloaded tens of thousands of times, and with it being as easy as Crtl+C, Crtl+V to make a copy it spread across hard drives around the world. The open source nature of it opened the door for people to make revisions and improvements throughout the file. I had gotten revision 3 and promptly began analyzing it in Solid Works. Some brief research was done on print shrink rates, I decided to add a +.03 sale increase to account for what I thought the PLA's shrink rate would be. The file was then loaded onto a SD card and inserted into my 3D printer. Estimated print time for a 100% infill with .10 layer height was just over 48 hours. 

A few days later, and the print had finished, it was time to break it free of the build plate and begin removing the support material to see the results. With the last few strands of support being liberated from inside the trigger guard, I was now holding an accurate representation of a lower receiver, but would it work? 

The answer was sort of, the lower accepted a standard 30 round magazine with ease, however there were some crucial issues. Some of the pin holes were not circular and scale was off when I tried mating it to an upper receiver, its was ironically +0.03 to big. This surprised me at the quality of my budget printer and the fact that I was using natural color PLA which is notorious for being tricky to print with. What it all came down to is we were simply holding a huge chunk of plastic in our hands that wouldn't be responsible for firing a bullet anytime soon. But I don't give up that easy, back into CAD I went for my own personal iteration 2.0. 

3D Printed AR No.1-06429.jpg

Iteration 2.0 was pried from the printer bed 48 hours later, rocking the Schreer Luck monogram in grey PLA.  Opting to return to the original scale of the part, as I learned the shrink rater would be easily dealt this down the road, crucial holes were resized so that I could drill them out myself, ensuring proper dimension and roundness. Ironically though, once again all I currently had to show for my efforts was a chunk of plastic, the fact of reality is I still needed all the components that go inside the receiver, including the most crucial part of a firearm, the trigger. Off to the local gun store I went to buy the parts kit which itself is not cheap. 

3D Printed AR No.1-06437.jpg

From the very beginning of the assembly process what was determined to be a negligible shrink rate, was working against me. I had to break out the files and slowly massage off one ten-thousandth a stroke, and the majority of spaces, to give the necessary tolerance for the metal components. Also on the Iteration 2.0 the receiver accepted a 30 round magazine, but it was an uncomfortably tight fit. It was working my way through this process that I came to the realization that this isn't something your average person could put together easily, like claimed. I will concede that I taught myself how to assemble a lower receiver on youtube, right next to a tutorial about how to make enchiladas, but there is still an element of being mechanically inclined when building one. Frankly it takes a lot of effort and trial and error, which I would realize by the end of it, its so much easier just to go buy one, an average entry level lower can run as low as $40. 

As the parts count began to build on the lower, I became less impressed. Compared to other machined lowers from metal, it felt cheap, not something I would trust my life to in many way, but I still had yet to prove if it actually worked. It remained promising and I finished up the assembly, with a satisfying click of the fire selector. Next it would come time to mate it to the upper receiver, which houses the bolt, firing pin, and barrel, basically where it all goes down. Which is the puzzling part as to why the lower receiver is considered the gun by definition, the only thing its good for by itself is throwing at someone. 

3D Printed AR No.1-06470.jpg

The final mating of the upper and lower receiver reminded me a lot of a second date, there was chemistry, but they weren't exactly ready to get together. With little influence from a dead blow, the bolts slipped into place and there was now a complete rifle, ready for a shakedown. It would have to wait for the weekend when the journey to the desert could be made, before bullet could meet firing pin.  

To say I was nervous would be an under statement, after all this was something that came of my 3D printer that I was about to try and shoot. I assured myself again that my countless weeks of research would ensure I had checked all the boxes. All that was left for me to do was to slip (push hard) in a mag, rack the charging handle, and aim. Bringing the rifle up to my shoulder I align my red dot over a target then pushed down on the safety with my thumb. The rifle was now hot, I had one task left to do to find out if it would all work, or blow up in my face, squeeze. 

The smell of sulfur filled the air, a concussion ran through my shoulder as a round exited the barrel headed down range. It worked, and it worked well, after a quick glance over to make sure nothing had broken, I sent a few more rounds out, then more, then finally the bolt locked back and I had shot my first mag through my very own 3D printed AR. 

To conclude, the purpose of this experiment was to gain a better understanding of the topic, having been interested in it for years and finally having everything fall into place for it to happen. It wasn't easy, not nearly as easy as starting my printer and waking up the next day to a fully functional assault rifle. It also needs to be mention that in my opinion 95% of this rifle is off the shelf components, that cost hundreds of dollars, by itself the lower receiver that was printed is a paper weight, and the concept of a 3D printed gun with the capabilities of an AR-15 that is fully 3D printed is far off in into the future. It hasn't changed me as a person, and its perfectly legal for me to have made this in my own home, however I cannot sell it to anyone. It is my rifle from the beginning and until the end. I wanted to do this, so I could understand and have had the experience, so I wouldn't find myself being ignorant on the topic. I can understand why people feel threatened by the rapid growth of this technology and how some people are choosing to create weapons with it, but that would happen regardless of 3D printing or not. There is a responsibility that comes with gun ownership and theres hundreds of thousands of people that use these tools on a daily basis, and with a user group so large they deserve innovation that benefits both gun users and non gun users. 


Alexander Schreer

Designer / Photographer / Creative Hybrid