

Here are the specs:
Chamber: 18"x4" Sch40 pressure rated PVC
Barrels: 60" sdr 21 tennis ball barrel and a 72"x2" sch40 PVC barrel
fuel source: 10" propane meter pipe (usually ran at 50-55 psi)
fan: 80mm cpu fan wired to 2 9v batteries and toggle switch
ignition: push button bbq ignitor wired to push button switch
ammo: tennis balls, soda cans, potatoes and whatever else i feel like 8)
I haven't measured its range or muzzle velocity and tennis balls don't due to well for damage pics, but it shoots pretty far. I've been gather info from this site for a while now and I think I put all of it to good use. thanks spudfiles

and here it is! the PPK-7000!
right side of the cannon showing the propane meter and the ball valve

left side of cannon showing the propane tank with regulator and the ignition/fan box

soda can after shooting it at a brick wall. sorry its the best semi-damage pic i could get. I'll try and get more once i find something to shoot at and more destructive ammo.
