[KenWittlief]

dont say no too quickly

the problem with using a pneumatic cylinder to launch things is the small size of the tubing and valves. You cant get a fast enough inrush of air to move the cylinder piston as fast as you need to

but dont give up, there are ways around this

one would be to rig up a stop, or trigger/release pin about halfway down the cylinders length. To shoot something you would pressurize the cylinder against the trigger pin. That will build up a volume of air inside the cylinder at 60PSI

then you pull the trigger out of the way. There will be nothing to slow down its movement this way, except the ball that is being launched.

I must point out, these cylinders are not designed to be slammed into their own ends, so if you do something like this you must put a mechanical bumper or stop that limits the motion of the piston, so it cannot slam the end internally. If not, sooner or later the end will blow out of the cylinder, with a great deal of force: someone could be seriously injured.

there are other ways - brainstorm the concept: use the cylinders to load up some other form of energy storage/release mechanism.