Mossberg 51773: The Mossberg 590A1 Magpul Series 9-Shot 12GAuge shotgun features Magpul SGA stocks and MOE forends designed specifically for the Mossberg tactical shotguns. The SGA stock features a spacer system for LOP adjustment, offers improved grip ergonomics, a recoil-reducing buttpad and optional cheek riser for use wtih mounted optics or raised sights. The MOE forend features extended length and front/rear hand stops for control. It is fully compatible with MOE rails, mounts and accessories.