Mechanical engineering student James Patrick recently uploaded a video to his YouTube channel showing off the fully functional PM522 Washbear .22LR revolver that he designed and 3D printed. With the exception of the firing pin, a few elastic bands that act as springs and the legally required amount of detectable metal, the entire gun including the body and cylinder is completely 3D printed. This is, to my knowledge, the very first functional repeating firearm ever made entirely (This doesn’t count, it has metal barrel inserts) on a desktop 3D printer.
The frame of the PM522 Washbear was designed to hold either a six or eight shot pepperbox revolver, however the six shot is printed in a more durable nylon material while the eight shot is printed in ABS with steel chamber liners for extra strength. Both barrels will fit in the same gun frame, so they are interchangeable. All of the stl files have been optimally orientated by Patrick in order to maximize the strength of the material and prevent failure. For instance, the gun frame is printed flat on its side while the revolver is printed standing up. By putting them together the frame is strong enough to contain the the pressure of firing and keep the cylinder layers from splitting.
In contrast, the 3D printed Liberator handgun designed by Cody Wilson holds and fires only a single bullet, and doesn’t always survive for a second shot. If what Patrick says about the PM522 Washbear is accurate, this is a significant upgrade from the Liberator, although he does warn that the gun isn’t intended for repeated usage. Patrick also suggests that subsonic ammunition is the best choice of ammo because it won’t break the sound barrier when it fires, resulting in no shock wave as the slug leaves the chamber.
Here is a brief video of the PM522 Washbear being successfully test fired:
Patrick makes it very clear that his revolver should not be printed using standard PLA material; instead he suggests all of the parts of the body be printed in ABS with 100% infill and maximum shells. However unless chamber inserts are used, the cylinder assembly needs to be printed with nylon, as taulman 3D’s Bridge Filament was the only material that has been completely successful. When the gun is assembled, Patrick used epoxy to hold everything together and to hold the stainless steel tubing in place so his gun meets legal requirements.
There is no denying that the PM522 Washbear is quite a cleverly designed firearm that uses some unique solutions to operate the revolving barrel. Instead of springs Patrick used some elastic bands, he suggests ¼ inch dental bands, to power the guns striker, trigger, and sear. A modified roofing nail with the tip grinded flat is used as the firing pin, and the cylinder was designed so when the trigger is at rest the pin will not be in line with the bullet cartridge, making it completely drop safe.
While Patrick has been working on his 3D printed revolver for months, it was just this week that he uploaded the stl files for sharing. Considering that the PM522 Washbear 3D printed revolver is far more advanced and usable than the Liberator ever was it remains to be seen if or when the government will notice. If you remember, the Liberator was ordered removed from the internet because the Government claimed that it violated the Arms Export Control Act, something that Wilson is currently fighting in court. How the government handles this should be interesting, and regardless of how they get involved it is certain to have ramifications for Wilson’s legal battle.
In the meantime, you can find the files for Patrick’s PM522 Washbear on his website here, for as long as they last. The stl files are included in the downloaded, as well as full printing, finishing and assembling instructions. He has also posted a five part design and assembly log that starts here.
What are your thoughts on this new 3D printed gun design? Discuss in the 3D Printed Revolver forum thread on 3DPB.com. Here is a video of Patrick explaining the design process of his PM522 Washbear: