Have you considered a shoebox and a guppy 4500 psi tank? It is an expensive way to go but it will also last a lot of time.
Thanks guys. You are making me think and will certainly look into it that combination.FWIW. Since my last post. I have also read the S510 manual. Neither rifle maker recommends using a hand pump due to their relative inefficiency in removing moisture.
So how does the Nitrogen bottle come into play?