Tippman 48ci bottle, what adapter for Foster fitting?

[Joe Smith]

Friend gave me this. Air rifle that doesn't want to fill. Was told to hook it up to a tank & give it higher pressure quickly as that will close whatever valves are open - and won't close with the normal electric air pump filling it.

What adapter do I need for the tank that has a Foster fitting for the air rifle?

Am woefully ignorant with these bottles - I'm sure it shows.

What I know is I can't get the rifle to fill with the compressor or my Hill pump. Willing to try this method & hope it works. Rifle was completely empty so I could put in a new O-ring & tape the threads on the fill port. That is where it was leaking - but now I can't get the fill started.