[quote="Pookydarts"]Slight deviation here, but still on the 'questions from new cannon builder' general theme...
What is the generally accepted 'Best' valve type for a 3000psi air cannon?
I've heard the term "hammer valve" and searched for it here, and even googled it with very little success.
I found a great site that had a valve description for a 'Girandoni' style air gun, does it look like one of those?
I only want to play with normal old air... (At this stage!

)quote]
For 3000psi, I would suggest either a piston valve (suitably built of course), or a hammer valve.
The Girandoni does indeed use a hammer valve, as do many airguns, antique through modern.(The Air Force Condor, is a popular example.)
My co-ax uses both.
http://www.spudfiles.com/forums/high-pr ... 12803.html
Don't be put off by assertions of how "hard" it is to make a piston valve.
Failures in this arena, can often be traced to poor workmanship and/or a simple lack of fundamentals.
They are exceedingly simple devices.
"It could be that the purpose of your life is to serve as a warning to others" – unknown
Liberalism is a mental disorder, reality is it's cure.