^^^^ good advice get a siphon tank and run her on liquid
I used a Panther VTS then a Puma for many years before getting my B2K bushy.
I ran liquid CO2 for best consistency but you sacrific shots thus I ran a 20oz on my back and got about 1000-1200 rounds out of her.
Put teflon tape on the rear adjustment screw this will help hold it in place.
once the gun is balanced it will hold a very tight FPS on liquid.
Iam looking to buy another PUMA to play with but they are scarce