Heres a short summary. :It's not glorious and it's not very pretty but it is a very simple and effective homemade. It's basically a Bow n' Arrow that shoots micros. It gets nearly exact range compared to a BnA with a sawed off tip with all ammo. Obviously because it's CPVC it uses stefans more effectivlely.
The way to make it is simply cut a piece of CPVC to the desired length. (a longer barrel will get more range, this is the reason for the coupler on the end of the barrel) To make the air actually power the darts out of the barrel get a pole of some kind, that is about 1/3 to 1/2 the length of the barrel. Put enough electric tape around it to make it mostly airtight as you are letting go of the pole, or plunger as we will call it. Then simply take 2 bungee cords, tape them to the plunger, and then tape them to the barrel. Make sure the bungees aren't too loose or the gun will not work properly. Here are a couple of pics of the plunger.
