not as elaborate as some of these pvc monstocities, but still fun to make.

Step 1: Materials

machanical pencil or spring loaded pen
tape
car or tv antenne
BBs
hammer or blunt metal object

Step 2: The Barrel and the Grip

first, take apart your antenne and find a cylinder that almost fits your bb

then hammer one end so the bb can almost get through but not quite
(you may have to trim it down so you can use the trigger later on)

Step 3: Trigger (simple)

find another pipe that is narrower than the barrel
______________
flatter the very edge of the pipe like this ______________>---

(sorry, my camera sucks)

Step 4: Firing

load your bb into the barrel and ley it go to the end
then load your sring the same way
now, insert your "trigger" and push agaist the spring untill both the bb and the spring fly out and hopefully hit somebody you dont like

Step 5: This Part Sucks

now the hard part is finding you spring lol
unless you solder the spring to you "trigger pipe"

MY TRIGGER IS AWFULL! Any sugestions would be great.

this was my first instructable so be nice. l8r :)