WarFairy’s 3D Printable AR-15 Bullpup

3D printing has been growing in popularity recently with 3D printed firearms and accessories making headlines over the past year or two. Well here’s an awesome new design that’s been released recently by WarFairy over on Reddit. Dubbed the Hanuman AR-15 Bullpup, it’s still just a prototype and requires the use of a buffer less upper (like the ARAK-21 or Rock River Arms PDS Carbine) or an upper with a .22lr conversion kit. The configuration up top is with an SBR upper with an overall length of 20″ with the configuration below sporting a 16″ upper with an overall length of 26.5″. Both configurations are just for display purposes as they’re not buffer less uppers. There is no safety so printing one out is at your own risk. Check out more pictures of the new AR-15 bullpup here. Check out WarFairy’s past creations here.


After entirely too long of a development cycle, I give you the Hanuman AR-15 Bullpup. It is very much a prototype, lacking a safety and adjustable LOP (outside of interchangeable butt pads), but should work without issue.

It requires a bufferless upper to function, such as the ARAK-21 or Rock River Arms PDS Carbine, or a regular upper with a CMMG Style .22LR Conversion installed.

The entire lower weighs 1.45 pounds when created in ABS, so material cost will be between 20 and 40 dollars depending on the cost of your material.

It is being released concurrently with the new FOSSCAD MegaPack V4.7 (Aramaki), along with a whole mess of new designs from a bunch of designers as well as myself.

To see the new stuff included in the Pack:

DOWNLOAD LINK for MegaPack V4.7 (Aramaki):

Ray I.

Long time gun enthusiast, archery noob, Mazda fan, Sci-Fi nerd, Whiskey drinker, online marketer and blogger. My daily firearms musings can be found over at my gun blog ArmoryBlog.com and Instagram.

Shoot me an email at ray.i@staff.thefirearmblog.com


  • sianmink

    a non-reinforced AR upper smashed to my cheek while firing?

    having blown one up in the past and seen it unfold like a bad taco, I’ve got one word.


    • nova3930

      I second that. I see that thing disintigrating after a very minimal number of rounds, quite possibly a single round….

      • David Knuth

        you do realize that a company 3D printed a full, working 1911 out of metal that has fired without a problem, right?

        • iksnilol

          True, but that lower isn’t printed out of titanium. It is printed out of plastic (ABS if I remember correctly).

          • David Knuth

            As a proof of concept, sure, but you could print out of any material available.

          • Giolli Joker

            Yes, but you can print it in ABS for 40$ with a 2k$ 3D printer or with a few hundred $ of metal in a 500k$ DMLS, that probably needs an entirely different drawing and program.
            This lower is designed to be made in ABS.

          • BryanS

            As are most of the warfairy designs. Once my heated bed is in and I get my extruder issues down, Im going to be printing one of his P90 style lowers from ABS. These guys are also working in the area of printing items in nylon these days as well.

          • Gregory Allard

            Current goal is Poly-carbonate

            That said the ABS lowers are at a point where no one can afford the ammo to test one to destruction

          • Gregory Allard

            2000 dollars is a high estimate New company’s May well and truly Break the 1000 mark with capabilities that years ago cost much more. what Fosscad is doing Is in a different realm of most 3d printing because we stopped being satisfied at just printing desk knickknacks.

            Expect to see 400 rounds from this before it will start seeing structural failure issues

            I got involved to cope with my dads death because of a gun bigots criminal harassment. Others do it simply for the pursuit of knowledge and the spread of data love

          • Gregory Allard

            Your printing the lower not the upper If any of these claims were founded There would be evidence of a traditionally Configured AR15 printed lower Causing the upper to explode.

            Though there is a common gripe about the rails on these uppers.

            Furthermore given the Fact that existing designs Can Survive 50 Beowulf rounds and 600+ rounds of 5.56 ammo (at which point they ran out of money for ammo) Breaking apart on the first shot is rather un likely…

          • iksnilol

            I am not worried about it exploding, more worried about it breaking.

            I like 3d printing but I won’t use it for stressed areas (except the lower). Mostly for triggers I find 3d printing useful.

          • Gregory Allard

            Again No one involved with Fosscad Knows how many rounds the current generation of lowers can handle Since none of us can afford a 1000 rounds To Purposefully Test a lower to destruction.Slightly older Designs have gotten to 600+ befor the Defense distributed folks ran out of money for ammo.

            These lowers DO work with .50 Beowolf rounds

        • nova3930

          I’m well aware of that. My comment has nothing to do with 3D printing but with the adequacy of the design, which IMO as a engineer, is inadequate and poorly thought out.
          As originally configured, a standard AR does not impart a signficant amount of force on the front pivot pin in firing. I believe this design will initiate a load on the front pivot pin which will over stress it and cause it to break out, worse if it’s printed and worst if its printed with that cheap ABS plastic.

          I think the issue would be alleviated by modifying the design to interface with the bottom rail, reducing the load and distributing it across a wider area.
          Anything else you want to inform me about?

          • Cornelius Carroll

            I had the exact same initial impression regarding the bottom rail. Now how to make that interface somewhat universal and not make breaking down the rifle significantly more difficult…. that would take some slick design.

          • nova3930

            I think you could just build in the rail interface where assembly would consist of sliding in the upper from the front. The wild card is the size of the pin retention structure on the upper, which I don’t know off the top of my head…

          • Atlas

            An AR15 front pivot pin joint between the upper and lower takes all the load when firing; the rear lug on the upper is a slot and there is clearance between the upper and lower at the rear of the receiver.

          • nova3930

            Yeah, and I think this setup will increase the load that pin sees significantly. It’s like people are reading around what I’m saying instead of what I’m saying….

    • guest

      Did you completely miss the .22 LR kit part, and that it does not use a buffer at all?

  • Eurocopter

    3D printing in titanium can apparently now be done, see this post on reddit:


    I assume these are modeled in CAD, and that this, and other lowers can be produced just as easily with the right equipment…

    • Steve Truffer

      You do have to account for the printing behavior of various materials, but yes, they are cad models. One thing DEFCAD discovered, going from Aluminum to ABS additive models means the model needs to be ~3% bigger.

  • The Hun

    It’s a start- let freedom ring. I christen thee the “FU Feinstein AR-15 Bullpup”

  • ColaBox

    Oh god that was never meant to be. Please put it out of its misery.

  • Mark N.

    Looks like it would put your face right above the ejection port and rubbing on the top rail. I bet that’s REAL comfortable….

    • Gregory Allard

      Warfairy was discussing a Rail cover/cheak rest for the next update

  • Justin William Officer

    Looks too much like a PS90 for me to even consider liking .

  • Paul Kisling

    Looks like an interesting plinker. I would not exactly call this a training weapon seeing as there are comparatively few bullpup AR type rifles. Those that do exist cost out the kazoo.

    Another problem is that by the time I could afford the printer and materials plus the upper I could have long had a Tavor to play with if I was into bullpups which I am not.