This is my first cannon, it is a very simple design consisting of 1 old fire extinguisher tank, 2 3/4" 90* elbows, 1 3/4" 6" long pipe, 1 3/4" t fitting, air compressor quick connect, 3 3/4" nipples, 1 modded 3/4" sprinkler valve, and 1 3/4 coupler fitted on a 3' long 3/4" pvc pipe for the barrel. T...