See:
http://maritime.org/doc/index.htm
40 MM Antiaircraft Gun, OP 820, 1943. The maintenance manual for the dual Bofors 40mm gun.
40 MM Mount Mk 4, OP 1329, 1947 describes the very widely used quad mount for the Bofors 40mm gun of WW II.
40 MM Antiaircraft Gun, TM 9-1252, 1951, is an Army service manual for this widely used single Bofors 40mm anti-aircraft gun of WW II.
40-mm Automatic Gun M1 (AA), TM 9-252, 1944, is an Army service manual for this widely used single Bofors 40mm anti-aircraft gun of WW II.
40-MM Wet Mount Assemblies (Single), OD 5853, 1947, describes modifications to the Army single Bofors 40mm gun for use on submarines. The manuals for the gun are in the ordnance section below.
rich