Ordnance provision system. [Ordnance catalog (ordnance provision system): Group A, Gun, automatic, 40-mm, M1 and carrirge, gun, 40-mm, M2 (AA), major items, maintenance parts and equipment required for maintenance of gun, automatic, 40 mm, M1 and carriage, gun, 40-mm, M2 (AA), addendum; Dec. 21, 1942.