Hello all! I have been airgunning for a few years now, and I am almost ready to stick my toe into the PCP realm of things. I have a very limited budget (3 kids in private school will do that), but I acquired through work this week, for free, a fairly large oxygen tank, which seems to have been used for medical purposes. It was fitted with an adjustable regulator with a max output of 15psi, but the the bottle pressure was rated to at least 3000psi. It even came with a handy stand to keep the bottle upright. My question is, can this bottle be used for compressed air, if fitted with the appropriate regulator, fittings,etc., or am I better off attempting to trade it in at the local filling station, or just buying a different tank? As I said, I am on a budget, and I pride myself in reusing/recycling when feasible. Thanks in advance.