(At least the same diameter valve as barrel for the best performance)

How do I go about a 3" valve? Just curious

yes around 100 psi.

Hi to all and thanks for such an informitave site. I have been a lurker for the last few days now and I finally got my cannon finished up. I wanted to show a picture of it. It is just a basic t-shirt cannon. 3" x 20" barrell and chamber with a 3/4" orbit sprinkler valve. I'm not real sure if it is ...