40mm Grenade Launcher

"“The only thing I can think of that would make the (MA5C) any sweeter would be an under-slung shotty or a forty mike mike.”"

- Anonomous UNSC Serviceman

The 40mm Grenade Launcher is an attachment available for the MA5B and MA5C Assault Rifles. Though never used in the games, it was originally meant to be part of the MA5B during the development phase of Halo: Combat Evolved, while it was still intended for the PC. As such, its canonicity was debatable until mentioned by Bungie in a description of the MA5C.