Been to the Diving shop that's about twenty minutes from me with the tank I got in the Tippmann from @rocketdogbert.   Got there and naively waltzed in, tank in hand only to be told they can't fill it because I didn't have the adaptor for the fill nozzle of the tank to match their tank.   Doh. Righto..   Go home get all the things from the box and headed back. Tool everything but the gun in case I was being stupid. Still no good.      Now, the li