A 3d printed nerf gun! It is quite powerful, much more so than an ordinary nerf gun. The components can (and should) be printed without support material. Overall it is a pleasure to make and shoot. http://youtu.be/fWqqkC2mWp4?list=UUbpQ7btFuliuTEXwwyfkYUQFirst start by printing all of the files. Then you can prep the non-printed parts. Cut a length of 3/4" CPVC just under 2 inches longer than the length of the large printed handle. line the CPVC up with the handle such that the back of the pipe is at the back of the gun. Then mark the pipe where the trigger sear extends up out of the handle. You need to cut a window in the CPVC that will allow the sear to extend up into the pipe, holding back the piston. I used a dremel to cut the rough shape and then filed it into the correct size. Once you have this window cut, you can work on the piston assembly. To start, drill a centered hole in the CPVC end cap just big enough for the long rod that was printed to slide smoothly into. You printed out a file called "New Piston Assembly". This print contains 4 parts, 3 of which are identical and one of which is taller and has a lip. Take one of the 3 flat washers with square holes and glue it right on the end of the long square rod you printed. Then slide the rod with washer through the end cap so that the rod goes through the hole you drilled and the washer that is glued on the end rests on the outside of the end cap. Once again, this is clarified in the first portion of the youtube video. Next, slide one long spring (or two short ones) down the piston rod so that the end of the spring rests inside the end cap. Glue another one of the 3 flat washers with square hole onto the rod, right against the spring. The final two washers from the piston assembly can then be glued together such that it looks like a cylinder with notch in the middle. This notch is for the o-ring. Make sure that when you glue these together the square holes align perfectly. Then glue this onto the end of the rod opposite from the end cap. You alternatively can first put them on the end of the rod (in the same sandwich configuration) and then glue them. You now should have something that looks like what the video shows. The final step is final assembly. Just follow the video and you should be good. The only pieces that aren't printed are an o-ring, some 3/4" CPVC for the cylinder, some 1/2" CPVC for the barrel, a 1/2" to 3/4" CPVC adapter, a 3/4" CPVC end cap, one hose clamp (I used another as a front sight), two springs, and a rubber band.