Answered: <R15> pneumatics component modification

On pneumatic cylinders, the back of the cylinder is flat. If the cylinder is mounted in a 1X2X1X?? C-Channel it can only pivit a small amount.
If the back of the cylinder was rounded so the cylinder could pivit when mounted in a 1X2X1X?? C-Channel, would the cylinder be legal? (see drawing)

Vex Cylinder.gif

No, this type of modification is not permitted. The rule you quoted specifically bans modifications of any type to pneumatic cylinders (pistons).