Instead of co2, you could use propel. I don't think propel has as high psi as co2. It is used for ballast tanks, torpedoes, and some missiles on rc submarines. To refill your gun just press the tire valve firmly against the supply can adaptor. your setup can have the storage tank and a solenoid air valve. the ball might freeze a little when fired from a rocket launcher but it will launch. all of the parts can be found at places like www.mikessubworks.com www.rcboats.com. You will need to wait for some of the parts. They are currently getting resupplied right now.
that brass tank can fill up the entire compartment (ballast tank) at least 25 times
I had a little leak from some broken balls I got rid of the decorating barrel. The tape was used as a spacer.
