Granted you have an air compressor, a BB machine gun (BBMG) is a very easy and effective device for shooting BB's at a high rate. The basic principle behind a BBMG is that by adding air into the chamber the BB's are resting in, the BB's will bounce around the chamber at high velocities and continue bouncing until it sends itself through the barrel. So, watch and learn to see how to make this BB machine gun. You'll need a some PVC caps, drill bits, PVC primer and glue, a blowgun, Teflon tape, sandpaper, and... well, just watch the video, will ya? It will show you everything you need to make this homemade BB machine rifle.