The M1 Combat Car represented the rather meek beginning of American World War 2 tank development. It was an all-machine-gun tracked platform featuring a crew of four in its compact dimensions and managed a production total of 113 units through the storied Rock Island Arsenal facility. The vehicle managed a very short operational service life due to the move by all major armies to reequip their armored forces with cannon-carrying vehicles - the United States being no exception. The M1 Combat Car served from 1937 into 1943 before being given up.
As was the case with many armies in the period between World War 1 (1914-1918) and World War 2 (1939-1945), the United States Army adopted a policy of light combat tanks intended to support infantry actions - though to skirt around period restrictions, the vehicles were termed "Combat Cars". A 9.4 ton design was accepted which incorporated the engine at its rear, a 360-degree traversing turret at center and a hull superstructure atop a Vertical Volute Spring Suspension (VVSS) system for cross-country travel. Armor protection was up to 16mm thick. The crew numbered five and was made up of the driver, section commander, gunner and loader. The primary armament was 1 x 0.50 caliber heavy machine gun and 1 x 0.30 caliber medium machine gun held in the turret through a side-by-side arrangement. Power was from a Continental R670 7-cylinder air-cooled radial engine developing 250 horsepower. Road speeds reached 45mph and road range was out to 100 miles. Dimensions included a length of 13.5 feet, a height of 7.4 feet, and a width of 7.9 feet.
Rock Island Arsenal outputted 89 of the initial M1 production model. This was then followed by 17 of the newer M1A1 models which incorporated an all-new octagonal turret design and redesigned running gear. The M1A1E1 was a short production run of a developmental type which installed a Guiberson T1020 diesel engine over the original's gasoline-fueled version. Production of this mark totaled seven vehicles. Then followed the definitive diesel-fueled model as the M2 of which 34 were eventually produced.
The M1 was used in an operational role during the early stages of World War 2 where all manner of armored vehicles were needed. Some stocks fought (and fell) in the Philippines campaign of 1941-1942 and operated by the Philippines military.
The "Light Tank M1A2" designated was used from 1940 onwards, replacing the "combat car" designation and classification of the series. This then led the full line of "M" series tanks fielded by the American Army since - the M2 Light Tank followed by the M3 Lee/Grant and, ultimately, the M4 Sherman. The M1 Abrams Main Battle Tank of today has reused the "M1" designation.