SpudFiles

Very well then, the air hose will act as dead space between the output of your piston valve and the projectile.

I think I'm missing something here....got a diagram?

i have two ideas...eithe ri connect the pilot exaust and the air chamber to a ball valve, when i open that(it will be spring powered) and all the air comes out. Or i have a two tubes one as exaust for the pilot and one from chamber to gun. which of the two is better?

I dunno, I don't see how either would reduce dead space.

If it were up to me, I'd put a ball valve before the air hose and a piston valve in your gun. That way you get the safety of keeping the air in the backpack till needed, and the reduction of dead space to almost nil.

the pressurized air would have to get to the gun some how tho...dead space still exists

True, you'd need a CO2 tank or something that can maintain a costant output.

Anyways, the dead space won't completely make your cannon worthless, just increase the pressure a bit.

true, to what pressure should i increase?

Ok i ahve an image for you people i hope it helps, this is my second idea, i am not quite sure how good it is. I hope it works