[KenWittlief]

decided to draw a diagram

1. the release pin is blocking the cylinder from extending more than half way

2. the cylinder is charged with 60PSI

3. the release pin is pulled. The business end of the cylinder has no fitting, so the low pressure air flows out freely

4. the ball is launched into tomorrow!

5. a mechanical stop prevents the end of the piston from slamming the inside end of the cylinder (not shown)

6. use a spring or surgical tubing to pull the piston back when the pressure valve is closed (not shown either)