Just a little update, got my Sprinkler valve setup now, trying to figure a way to attach it to the Barrel any ideas? its 3/8" inside and just over 1/2'' outside
also i have about 2 feet of hose for my air trigger, does it matter how much hose i have, i have a voice in my head yelling "less hose!"

not sure how to make the piston valve i just tried to search it on the site and got about twenty thousand results, a link of a simple one would be awesome also i do have a Sprinkler Valve not sure how to set it up though and if its even the right kind, again picture> http://i38.photobucket.com/album...

Im working on my launcher, im using a quick connect and a ball valve, for direct connect to my air compressor and if i want a portable air source a female connector on a bottle cap with a 16 OZ bottle (when my bottle wears out i can replace it), the barrel is about 3/8" inside (a blow gun tube) tape...