Technical bulletins. ORD 222. Tank, medium, M4 and M4A1, carriage, motor, 105-mm, howitzer, M7, carriage, motor, 155-mm gun, M12, carrier, cargo, M30 (T14), vehicle, tank recovery, M31, M32, and M32B1, tightening of exhaust collector ring clamps on Continental R975 series engines; Nov. 20, 1944. n. p.