Tweaked NERF Dual Gun Connector * added ammo holder for 4 rounds * added center ramp for locking in place * ammo holes have a flat side and a pin to hold the ammo securely Blog posting: marcuswolschon.blogspot.de/2012/09/mount-nerf-gun-to-nerf-gun-with-ammo.html License is CC-BY-NC-SA So you may make one yourself and improve the design but not sell the design or made parts.