A quarter of a mile, with the right mass projectile, of the right shape and cross-sectional area would not have difficulty travelling a quarter of a mile. I am open to constructive criticism, but don't be gormless. I actually do not have a huge amount of time for building cannons because I am half w...

so I had another look at the piston valve, came up with a few more idea's. But i need help deciding what would be the best chamber :S any suggestions?

Will de Brett yeah I made an account will.

Thank-you for the warm welcome. I mean I have made pneumatic cannons in the past, to a nice result and learning curve lol. made a sprinkler valve with 3/4" porting, but it can still throw a projectile a quarter of a mile. I have only really built electro-magnetic gun style things and solid rocket fu...

So I have just got a nice new robust "piston valve" with a blowgun pilot, And I thought I should come to this website for inspiration on making a cannon with this, so far I was thinking along the lines of Mid-sized sniper rifle style thing, but The piston is 1" porting...which is quite big. Any idea...