I hadn't realisted the barrel-projectile width disparity.

Yes, that's definitely your problem. Even a 1/8" gap would be far too much.
thanks! experimented a bit with padding it to make it slightly loose in the barrel (but not so it rolls down it on its own) and it flew out about 3 meters. made it ...

Crna Legija wrote:How well do the balls fit, 2 1/2'' barrel for 1.6'' projectiles big difference.

it's a 2" barrel, around 2.5' long. it fits fairly well but is of course not snug, may try sleeving sdr 21 inside of it to see if it helps if I can find it

jackssmirkingrevenge wrote:Your valve is probably "honking" (rapidly opening and closing), you should think about modding the sprinkler valve for a more efficient manual piloting.

according to the wiki, it should only decrease the muzzle velocity by 10% -- would that really account for it not working at all for me?

Hi lads

I built a cannon using 2" sch40 pipe ( 2.5'ish barrel, 2' tank ), and a 1" sprinkler valve w/ solenoid which is hooked up to 27V (3 9-volt batteries).

When I pump it up to 60 PSI the golf ball inside only goes maybe a quarter of the way up the barrel, even if it is not angled there is not ...