It's a 6mm barrel

How could I take a tank (about the size of a paintball tank) with a pressure of 300 psi and regulate it to 60 psi? How long would a cloud last with that?

Man, if you want to make an good cannon for use in airsoft, I belive the only way is to make a grenade launcher for something like this:

Thanks for the answers. VH_man, if you don't mind sending me your plans, I would be happy to receive them.
My first idea was to do what jackssmirkingrevenge's link showed. Has anyone ever done anything similar to that? If yes, how is the performance of the gun?

Hi. How can I make a BBMG with a smaller ROF, for use in airsoft? It would have to shoot around 300 FPS and 10 RPS. All the guns I found fire about 50 RPS, and my BB budget it limited.
Thanks

http://www.boltsniper.com/
May give you some ideas.

I'm from Brasil. All the sprinkler valves I found were from outside the country, so the price would be the valve's+about 15 USD for the shiping+a price for the product to enter the coutry(wich is +- the price of the valve).

Thanks for the answers. About the sprinkler valve, I'm having trouble finding one in my country. How does a gun that has a sprinkler valve works?

Hi everybody, I'm a newbie in pneumatics, and I was wondering if anybody has a good way of getting more than one shot before I have to refil my chamber. Since I joined the forum, I've been looking for plans, but most of them said that I would need to have an air compressor conected to the gun. I onl...