I made a YouTube video showing this part in detail here: http://youtu.be/pGgKaY6h6t0 -If made correctly, this will allow breech-loading for a Nerf football launcher. This should only be used in a safe, field approved compressed air Nerf football launcher in a professionally run game of scenario paintball. It is designed to use Nerf brand Pocket Vortex and Aero Flyer foam footballs only. Do not use anything else. -Glue a piece of 2" Sch 40 Slip (no threading) PVC for the barrel. The length of the barrel is up to you, but 2' seems to work. The compressed air comes in at a 45 degree angle from a female threaded 3/4" NPT pipe section. The loading door fits in nicely to the breech, and locks closed with a slight twist. The seal is not airtight, but does function well. I have tested this design myself, and even played with it in a game of scenario paintball. -The height of the print should be 70.55mm when layed flat. The overhang holding the loading door on is a bit of a problem, but I printed mine without supports and only had to do a bit of cleaning. Use as much infill and layer thickness as you can, the more the better. -This design is meant to briefly channel rushing air, not hold it. The design is not meant to support the weight of a launcher or barrel, so add a support to take the structural stress off of the printed part.