Ordnance provision system. Ordnance catalog (ordnance provision system): Group F. Light, instrument, M1, M2, M3, M4, M5, M6, M7, M8, M9, M10, M12, M13, M16, M17, M18, M19, M20 and M23, major items and maintenance parts required for maintenance of light, instrument. M1, M2, M3, M4, M5, M6, M7, M13, M16 and M17, addendum: Dec. 12, 1942.