In terms of dead space, disregarding the 4 way cross, anything else dead space or unneeded?

ive actually got an over-under one right now. 2' of 2" for chamber then a 1" modified sprinkler and then a 3' by 2" long barrel. First one i made. Its not that im copying that design, i just cant seem to wrap my head around piston design, so seeing this style coaxial is something id want to look in ...

Mostly looking for feedback. From my point of view, it would work, but is there a way to make it more efficient? Just asking for opinions on the design.

http://www.armoredfistpaintball.com/bergles_cannon.htm
Think this would work? Ive never seen this design before, just asking for some input before i get into it.

Wouldnt the weight of the ball at the contact points prove to be too much to spin it?
This sorta reminds me of the experiment/trick where a ping pong ball is "levitated" above a hair dryer but is kept in place and at a consistent height by the air flow.

pretty cool. i found instructions on the net for DIY glowsticks made from luminol and another component. could be a cost effective alternative to buying sticks and you could vary sizes

Insignia Pilot. I got the 4gb model and its great. Even supports Bluetooth wireless earphones, also made by insignia so compatibility isnt an issue. The player is like $175 and the headphones were $50. Best buy carries them and i think theres an 8gb model too.

i found about 4 stairway handrails at a house that was getting gutted. cut them into 2 inch lengths and they fit perfectly in the 2in barrel pneumatic. pretty good penetration on wooden fences but they go on forever over my lake lol

I saw a design once where a guy mounted a pneumatic to an exercise bike and as he pedaled it pressurized the gun. http://www.popularmechanics.com/home_jo ... ?series=27

Someone already pointed out the use from No country for Old men. But the movie Smoking Aces had a similar device that one guy used. Pretty cool though

check out the book backyard ballistics, i think theres plans or at least a theory for it

Found this on Hackaday.com

nice gun. what do you mean about the ballvalve

so since summer time is around ive started shooting water out of my pneumatic gun. since the water basically mists after 15 feet, i thought of a way to make a nozzle. i havent seen it before on this site and heck, it may not work but here goes. For a 2" barrel, secure a 2" female thread piece to the...

how does this valve work. i understand the piston concept, but is the valve body also the chamber? could someone post a pic of a gun that uses this style of piston valve?