Howitzer, 105-mm, M2A1; Carriage, Howitzer, 105-mm, M2A1 and M2A2; Mount, Howitzer, 105-mm, M4 and M4A1 technical manual 105-mm howitzer M2A1, 105-mm howitzer recoil mechanisms M2A1, M2A2, and M2A3, 105-mm howitzer carriages M2A1 and M2A2, and 105-mm howitzer mounts M4 and M4A1 Machine gun mounts for trucks/ By John Vink BSc, 6th US Armored Division (ASC).