scba tank from a firehouse.

you would only need a fill station. (and any probes specifically for your guns if they do not have a foster fitting on them)



if you want a cheap one...this one....

https://www.ebay.com/itm/6000PSI-CGA347-Paintball-PCP-SCBA-Fill-Station-Charging-Adapter-With-24-Hose/283365964074?epid=10015847425&hash=item41f9ed792a:g:M0UAAOSwkAxcWJ5s





and a more expensive one but good quality is the stikman....

https://www.ebay.com/itm/STIKMAN-SCBA-PCP-Fill-System/323720604238?hash=item4b5f406a4e:g:1FcAAOSwIr5cMV~y&frcectupt=true





i have had the cheap one for a while now,

and it does a fine job of filling my guns.

Yes you can use fire fighter subs tank. Just check date. These tank have a 15 year life. Also 5 year hydro life. Usually fire station give them away after the 15 year so not really useful anymore. If it's still in the 15 year life, get it hydro test. Also you gonna need a fill station/hose/fitting to make it fit on airguns

Actually the pictured tank appears to be Steel since the dates are stamped and would not be on the 15 year retirement schedule if it is steel.

Hoop-wrapped aluminum. From the bottom pic it looks to have made in '04 so its at the end of its lifespan. Use at your own risk and not around others. These tanks are tough but fd's beat the hell out of them. BTW, was it tested in '18? HW cylinders have to be tested every 3yrs. Just be SAFE. 4300psi is nothing to jack with.