izod wrote:so in a nutshell

big hole + big air + big speed = big distance

Lets look at the various parameters:

barrel length: the longer the barrel, the longer the air will accelerate the projectile. This happens to a certain level though, depending on your chamber size. It is possible to have a barrel so long that after a point the projectile actually starts to decelerate.

chamber size: the bigger the chamber, the more air there is to push the projectile, but again there's an upper limit - once the projectile leaves the muzzle, adding more air is futile.

pressure: Force = pressure x area, so the bigger the pressure in the barrel, the bigger the force on the projectile, so more pressure always equals more power.

valve speed: the faster the valve opens, the faster pressure builds in the barrel, so more force

valve flow: same as above, the bigger the flow the faster the pressure buildup.

You mentioned distance, if you're shooting potatoes then more power is not necessarily better, if the potato disintegrates in the barrel then you're screwed.

If you just want to go further, then optimising your projectile is one of the best things you can do independent of your launcher.

A long thread but worth a read if you really want to push the limits:

http://www.spudfiles.com/forums/spudgun ... 22491.html