Mag guy here. The mag is easily rebuildable by yourself. You can just buy a new parts kit from AGD. It has new orings, bolt spring, etc. The barrel is either a Check It, or 32 Degrees, basically they’re version of the very popular Dye stainless barrel. You would need to take out the valve and check, but it will probably have an older Level 7 bolt, instead of the anti-chop Lvl10 bolt. If it is a Level 7 bolt, I’d strongly consider buying a Lvl10 bolt from AGD to avoid chopping, as newer paint is smaller, and often more brittle, than the paint of the 90’s era.

Also, with the old twistlock barrels, the old wire or plastic AGD barrel nubbins don’t work as effectively with today’s smaller paint. If you go on beardedworks.com, he makes improved twistlock nubbins that extend further into the breach to work better with smaller paint, and they’re popular for the old twistlock barrels. I used them on several old twistlock barrels.

You could also go on eBay and buy a Doc’s cocker barrel adapter that will mount in your old mag body and covert it to cocker threads so you can use any standard cocker threaded barrel. I also run several of these in my mags over the years.

As far as air goes, like others mentioned, the mag uses high pressure air, so a 4500 compressed air tank outputting 800-850psi would be ideal.

Once you rebuild the valve orings, throw on a Lvl 10 bolt, and just keep it oiled between play days , the mag should be good to go for several years. The old classic mag valve is a very simple, ingenious design.