[Ernst]

You could replace a lot of you nuts and bolts with lightweight rivets. I can't see much of your pneumatic system, but if you have a lot of brass you should replace it with more plastic fittings and tubes. If your shooter has an adjustable height, you may want to consider fixing it to one position and adjusting the flywheel speed to control disk trajectory.

In the future, your tower probably doesn't need to be as strong as you made it this year. Judging by the pictures you posted, Your tower seems to be made of the same type of stock as your drivetrain, which is overkill.