I'm thinking about building a propane injection system for my cannon but I'm not sure where to start. Can somebody point me in the direction of a set of plans or how-to article that will help me determine the size of the charge etc for my gun?

Built a new cannon, this one for some reason, with a better C:B ratio doesn't seem nearly as good as the first. I used 3' of 1.5" sch40 for the barrel, and calculated back from that to get a 13.5" length for a 3" chamber at roughly 1.5:1. With all the fittings etc, it seems the C:B ratio is bigger t...

I'd chalk it up to being totally green. I had an idea of the basic construction and just whipped it together before ever looking on the web. It fires a lot better than I imagined it would given the barrel/chamber ratio, but that might be helped by the fact that my spuds are sitting probably 8" from ...

My first cannon, the combustion chamber is short 5" long, 4" dia. with a 5' long 2" barrel. I'm already planning a bigger gun, but this one has proven itself quite capable of launching a spud over 150 yds.