your links dont work on my computer, you should check it out.

I am not sure you link works either

PS I looked it up and vapor pressure of propane is up to 170 psi when at 100 deg F. So I guess\ you could refill a propane tank, just be carful they ar not designed for that use.

Also I am not sure about refilling a propane tank with compressed air. Propane is a liquid when compressed and thus does not require nearly as much pressure as you would need with air.

the problem That I see is that in order to push out all the combustion by-products you will have to add a lot of oxygen after each shot. If you plan on adding enough propane to have a complete reaction be carful the force will be about five times bidder and much faster. The other alternative is just...