Standard nomenclature list A to R (with omissions). G-102. Ordnance catalog (ordnance provision system): Group G, Half-track vehicles, car, half-track, M2, carrier, personnel, half-track, M3, carrier, 81-mm mortar, half-track, M4, carriage, motor, 75-mm gun, M3, sec. 15B, Frame group; Sept. 1, 1942.