SpudFiles

Hello spudfiles. I have recently created perhaps my greatest pneumatic cannon to date! I call the beast "The Goblin". As far as the specifications go, I run the gun at around 90-120 psi using a Palmer regulated paintball CO2 tank. I'm using a standard QEV and slide valve set up to enable semi-automatic fire. Ammo is stored in an off the shelf 200 round paintball hopper that fits almost perfectly into the 3/4 inch pressure rated PVC I'm using as a barrel. The air chamber is made from 1/2 inch PVC. As far as the cosmetics go, I'm aware it doesn't look like a real firearm, and that is fine by me. I prefer its striking green color and the "safety" it provides. I do not intend to use this gun in any paintball matches, its simply for target shooting in my backyard. I'd love to hear what you guys think and I hope to get "damage" pictures up soon. Thanks!

Nice good clean build. I recommend 3/4 cpvc for the barrel, I used it in mine and it is so much of a better fit on the paintball than normal pvc:

http://www.spudfiles.com/pneumatic-cann ... 25537.html

Maybe you could mod the qev for chamber filling (I think that's what you would call it) and pull a 180 on the bottom chamber, so that you could mount the tank in a shoulder-stock type position. Then you could trigger it with a blowgun.

Looks good
How many shots do you get per tank?

Not bad, is there some sort of bolt involved? Also, how do you stop the balls rolling out before firing?

Believe it or not, the pipe I'm using as a barrel has an almost perfect seal with very little blow-by. I think its a threaded pipe for a sprinkler. I have not yet tested it on a full tank of CO2, but I should get around to it soon. Prototyping uses a lot of gas! I'm curious about how to include a blow-gun as a pilot valve. Is there any link or diagram you could include giving more details? Currently there is no bolt, and balls do occasionally roll out before firing, but it's not a big deal. I really appreciate the feedback and I look forward to seeing some of your cannons in the future. Thanks guys!

Easy Detent system to keep your paint from rolling out of the barrel:
And sorry for late reply, but here's how to use blowgun: