Hi,
thanks for your answer.
I browse a bit the pneumatic cannons forum. It seems that many designs (all ?) are build using highly compressed air, and vavles. I was looking for something less powerfull: I need to reach about 30 or 40 meters.
I will browse the forum again
Yours

Hello, When I was a boy (I'm 63), I remember a compressed air gun that works approximately like that: - You compress the air by sliding a tube beneath the barrel, - You insert a projectile, - You fire. I'm looking for something similar to launch tennis balls to my dog. One key point is the ability t...