5. Barrel and Spring Design #2 through google sketchup. We can cut the PVC pipe and glue four plane plates under it. Although both ends are open in this diagram, one side of it has to be closed. So, in this barrel, the ping pong ball will be inserted to the top semi-circular hole of the barrel. The spring will be reloaded by the bump that is going to move through the central groove (circled red in this diagram) by motor and chain. This is (Lawrence)'s Idea and please make any modification if you have better idea
6. Barrel and Spring “ Hop-up" system in the air soft gun: It’s basically putting a spin in the ball by placing a bump in the barrel. This could be applied to our machine. By making a "Variable" hop-up (maybe made by rubber?) we can control the spin and our machine can then perform with more functions! so lets think about this idea too. The hop up system will definitely be useful, we can just add a rotating pipe joint, with a piece of rubber attached in its interior side, in front of the barrel to create different types of spins, including backspin which is the hop up.
![Front End Design ,[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)