Called the Hanuman, this is a 3d printed bullpup by Warfairy a fosscad member. The bullpup is designed to work with bufferless AR-15 upper receivers. salsashark037 had an ARAK and a 3D printer so It seemed like a good idea. The lower functions well enough. salsashark037 says it “works as advertised”. The files came with printable takedown pins, though he opted to use some steel ones that he had lying around the shop. The trigger has an odd take-up, but crisp break. The reset can’t really be felt, but it can certainly be heard. He has a Wilson Combat 4.5lb single stage trigger in the rear of this rifle, so the take-up is due to the linkage. He doesn’t have a pull gauge, so can’t tell you what it is with the extra spring on the front trigger.
Due to the US requirement of an overall length of 26″ for rifles with a 16″ barrel (without being an SBR), the files include a 3″ buttpad extension. If you have a 20″ barrel you might be legal (double check) and the buttpad won’t be required though it does make a better check rest than the 1913 rail. salsashark037 did all of his testing with the extension installed. With the extension, the rifle balances well. The center of mass is right above the main grip. Though this grip is well below the center of mass. It feels very top heavy. If you haven’t bought your 3d printer yet maybe this will convince you?