I have a few PCP's. Some get 30 or so shots per fill and others get down to 10 (Benjamin bulldog). I have a young heng compressor that I fill them with but the problem is that I have to walk down a flight of stairs and from my barn to my garage to my compressor to fill them up. I was considering getting an SCBA tank to fill and keep in the upstairs of the barn to refill for longer shooting sessions. My question is how big a tank should I get? How many "gun fills" should I expect out of say a 3 liter SCBA? Weight isn't really an issue and I'd rather have the largest tank I can get to keep from walking up and down stairs. Now I have a few steel tanks that were used for nitrogen, helium, CO2/Argon for welding, can I retrofit an SCBA valve to those? They're pretty large in comparison to SCBA tanks, approximately 1.5-2x the size I'd guess. I'm not exactly sure of their capacity. I'd just rather have a fill tank in the barn instead of schlepping to the garage every 10 shots when I'm working with a gun like my bulldog. Guns like my .177 marauder is no big deal because 30 shots later I'm ok with the walk.
Forget about using any of those welding tanks!! None of them have high enough working pressures to be of any use for airguns. A three liter tank should work fine for you. You can use one of the on line fill calculators to figure out how many fills for each gun that you have. Make sure that you're using appropriate moisture filters on the output of your YH. Moisture getting into aluminum tanks can cause severe corrosion in a matter of months.
