M103 Heavy Tank

The M103 heavy tank served the United States Army and the US Marines during the Cold War. Until the development of the M1A1 in the mid 1980s, it was the heaviest and most heavily-armed tank in US service. The M103 was manufactured at the Detroit Arsenal Tank Plant and the first units were accepted in 1957.

Like the contemporary British Conqueror tank, the M103 was designed to counter Soviet heavies such as the Josef Stalin tank or the T-10 if a conventional World War III broke out. Its long-ranged 120 mm cannon was designed to hit enemy tanks at extreme distances, but it was never used in combat. Of the 300 M103s built, 80 went to the US Army, and 220 were accepted by the US Marine Corps, to be used as infantry support.

M103 Heavy Tank
Type	Heavy tank
Place of origin	United States
Service history
In service	1957 - 1974
Production history
Manufacturer	Chrysler
Number built	300
Variants	M103A1, M103A2
Specifications
Weight	65 short tons (58 metric tons)
Length	22.7 ft (6.99 m)
Width	12.22 ft (3.76 m)
Height	10.49 ft (3.23 m)
Crew	5 (commander, gunner, driver, 2 loaders)
Armor	180 mm (7.1 in) or 7.34 in (186 mm)
Main armament	120 mm gun M58, 34 rounds
Secondary armament	2×.30-cal (7.62 mm) M1919A4E1 machine gun (co-axial) 1×.50-cal (12.7 mm) M2 AA machine gun
Engine	(M103A1) Continental AV1790 12-cylinder air-cooled gasoline (M103A2) Continental AVDS-1790-2, V12, air cooled, twin turbocharged diesel 810 hp (604 kW) 750 hp (560 kW)
Power/weight	M103: 12.4 hp/short ton M103A2: 11.5 hp/ton
Transmission	General Motors CD-850-4A or -4B, 2 ranges forward, 1 reverse
Suspension	torsion bar
Fuel capacity	280 US gallons (710 liters)
Operational range	M103: 80 mi (130 km) M103A2: 295 mi (480 km)
Speed	M103: 21 mph (34 km/h) M103A2: 23 mph (37 km/h)

The successive versions of the M103 shared many components with the M47 and M48 Patton tanks and the M60, which, with the exception of the M60 (a main battle tank) were all considered 90 mm gun (medium) tanks. Tracks, rollers and suspension elements were the same, with some modification to take into account the greater weight. The engine and transmission were never modified enough to give the extra power needed for the greater weight of the M103, and as a result, the tank was relatively underpowered and the drive systems were fragile.

The turret of the M103 was larger than that of the M48 or the M60 to make room for the huge 120 mm gun and the two loaders assigned to it, in addition to the gunner and the commander. The driver sat in the hull. The gun was capable of elevation from +15 to -8 degrees.

Armor

The armor is made from welded rolled and cast homogeneous steel of varying thickness.

• Hull front: 100 mm to 130 mm (4 in to 5.3 in)
• Hull side: 76 mm (3.1 inch)
• Hull top: 25 mm(1 in)
• Turret mantlet: 250 mm (10.2 in)
• Turret front: 180 mm (7.34 in)
• Turret side: 76 mm (3.1 in)
• Turret top: 38 mm (1.55 in)