Developed from the highly successful French Brandt Mortar in 1935, the American M1 Mortar is an 81mm weapon. During WWII, the M1 was supplied to every U.S. infantry battalion, and was also mounted on the M3 Half-track. Producing a rate of fire of eighteen rounds per minute, with a muzzle velocity of 700 feet per second, the M1 could launch rounds up to 1.9 miles. Ammunition included both heavy and light explosive rounds, smoke, illumination and phosphorus / incendiary rounds. The weapon was typically serviced by a crew of 7-8 personnel, including a squad leader, gunner, assistant gunner, and ammunition bearers. The one drawback of the M1 was that the tube, mount and base plate weighed roughly 136 pounds. Starting in 1951, it was replaced by the considerably lighter M29 mortar. Produced in 1943 by the War Department, this restricted field manual was standard issue for M1 Mortar crews. It includes sections on maintenance and care, as well as information on the training of crew members. This includes chapters on the use of fire control instruments and sights, marksmanship and adjustment of fire, and advice for instructors. This manual has been reproduced in its entirety, with care taken to preserve the integrity of the text.