help for choosing the type for my new gun

[dilweed]

hello i am tired of making crappy ball valve guns. I have an idea of a piston valve but these are the things im looking for:
Small air chamber (maybe a 5 cm)
Efficient but easyish valve
A ton of power for 100-180 psi
more power than a balve valve gun
i would be happy if it can propel a 4 milimeter bead at 600+ ft per second on at least 140 psi.

[jrrdw]

Seems to me you got it figured out pretty much. Maby a smallish copper sniper style piston valve. Easy, inexspensive, plenty of snipers here to model after.

[MrCrowley]

A 5cm what? Diameter? Length?

This cannon of mine here easily gets 600fps+ at 100psi, should be no trouble getting a small projectile that fast.

http://www.spudfiles.com/forums/crowley ... 13459.html

I think you'd be happy with a co-axial, it's an easy piston valve to make.

[dilweed]

thank you very much for your replies, i want to use something like a 5cm long chamber and about 2 cm wide in circumfrence