During WWII many countrie did not think that armoured personnel and weapon carriers for conveying infantry and weapons in the battefield were very useful. As the mobility of tanks increased, it became impossible for infantry on foot or in unarmoured wheeled vehicles, partly armoured halftrack personnel carriers, etc., to perform operations in concert with tank troops. Motorised infantry in wheeled or halftrack personnel carriers were also vulnerable to nuclear weapons. Owing to the improvement of projectiles adapted to explode in the air to kill exposed men, it became necessary to give armour protection to advancing infantry. By the beginning of the 1970's carriers for giving proximity fire support to combined arms teams comprising tank force, mechanised infantry and armoured cavalry reconnaissance force, were developed on the basis of the armoured personnel carrier. In 1954, the US Army Material Comand declared a plan for a light, full-track, amphibious air-portable armoured personnel carrier. The M113 was started jointly by the Weapon Manufacturing Div. of Ford Machinery Corp. (FMC) of San Jose, California, and by Kaiser Aluminum Chemical Corporation (KACC) of Bristol, Rhode Island. Later, four each of the improved models, M113E1 and M113E2 were made. After tests the M113E2 was officially accepted as the M113 Armoured Personnel Carrier in June 1959. As the M113 family, the following vehicles were manufactured: M106 Armoured S/P 107mm Heavy Mortar Carrier; M125 Armoured S/P 107mm Heavy Mortar Carrier; M125 Armoured S/P 81mm Mortar Carrier; M132 Armoured S/P Flame Thrower; M730 S/P AA Missile; M741 Armoured S/P 20mm machine gun; M577 Armoured Command Post Car; M548 Cargo Carriers, etc. As the M113's successor with a longer range of action the M113E2 with a diesel engine was constructed in May 1965. After tests, the M113E2 was officially accepted as the M113A1 Armoured Personnel Carrier. The production of the above mentioned family including the M113A1 totalled 60,000 units by 1975. From 1965 on, the M106A1 Armoured S/P 107mm Heavy Mortar Carrier was supplied to the following units: heavy mortar platoons of support companies in tank and mechanised infantry battalions of armoured divisions, mechanised divisions or infantry divisions, and mortar squads of armoured cavalry platoons. The M106A1, a light-weight carrier of the M30 107mm heavy mortar, permitted both the mounted and dismounted firing of the mortar. It had a crew of six and its dimensions were 4.93m long, 2.86m wide, 1.99m high, weight 11.9 tons. As auxilliary armament, an m2 50-calibre (12.7mm) Browning heavy machine gun was mounted. Its maximum speed was 68km/h, range 483km.
U.S. M106A1 Arm SP Mortar Kit - CA216