Shooting Duel Tree (Nerf, Air Soft, BB Gun)

I've designed this for the Rival Nerf guns. Disclaimer: The gun has an upgraded spring and can handle the force required to spin it from one side to the other if you hit the target square. I'm not sure about air soft guns, due to the lack of mass of an air soft ammo, it would take a gun that can shoot with a high velocity. The swivel arms are webbed to reduce the mass so the Rival ball can move it. I don't thing it would be necessary to web the arm if you intend to use a BB gun. I would make the