Scuba tanks have two regulators one attaches to the bottle one is attached to the mouth piece. If i was able to get a spare reg and cut the hose in between the bottle and mouth piece and attach a female quick disconnect could i attach this to my gun?
the hose on my current reg is rated to 300psi so i could extend it with compressor hose pipe(also rated at 300psi).
Does any one know if the intermediate pressure (after first reg) could be different for different brands?
Can a sprinkler valve handle 140psi or higher?
http://entertainment.howstuffworks.com/scuba1.htm
First stage - The first stage attaches to the cylinder. It reduces the pressure from the tank (3000 psi or 204 ATM) to an intermediate pressure (140 psi or 9.5 ATM).

SCUBA regulator, showing second stage (left) and first stage (right)










