Ordnance provision system. Ordnance catalog (ordnance provision system): Group E. Gnn, 8-in., Mk. VI, M3A2 and carriage, gnn, barbette. 8-in., M1. major items, maintenance parts, and equipment required for maintenance of gun. 8 in., Mk. VI. M3A2 and carriage gun. barbette, 8-in.. M1. addendum; Dec. 26, 1942.