In fact, when M103 was born, heavy tanks became obsolete. Many countries have switched to using main battle tanks.
Beginning to be put into the payroll in 1957, the M103 was the heaviest tank the US had ever built before M1 Abram appeared. At that time, the weight of 60 tons of M103 was a huge number, when most other tanks were only 40 to 50 tons.
The power of the engine was not commensurate with this weight. This made the tank move very slowly, the range was limited.
Following contemporary American design philosophy, the M103 was built with a two-piece, cast elliptic armor scheme, similar to the M48’s design. The new hull that would save weight while being optimized at all angles for maximum sloping effectiveness, saving thickness and therefore weight.
The driver was placed in the centerline of the bow, allowing better glacis designs. It featured seven road wheels per side, mounted with long-arm independent torsion bars. The 28-inch track was shoed in steel backed rubber chevron tracks.
The Continental AV-1790 engine was placed at the rear of the tank, and produced a maximum output of 810 horsepower, fed through a General Motors CD-850-4 two-speed transmission. This allowed the 60-ton heavy tank to achieve a maximum road speed of 34 kilometres per hour and a maximum climbing gradient of 60%.
The resulting performance of the tank was dismal; being severely underpowered and very fuel intensive. This presented a host of logistical problems for the vehicle, most prominently the extremely limited range of just 130 km. Though this was partially corrected with the introduction of the AV-1790-2 diesel unit, it would remain cumbersome and fuel-thirsty for the majority of its service life.
The M103 was designed to mount the 120 mm M58 gun. Using standard Armor-Piercing Ballistic Cap Tracer Rounds. In its configuration, this gun was able to score hits at 2,500 to 3,500 m with good accuracy. The commander could select from 34 rounds of either M358 Armor-Piercing Ballistic Cap Tracer Rounds or M469 HEAT shells, mounted at the rear of the turret and in the hull. With both loaders, the maximum firing rate of the gun was five rounds per minute, owing to the design of the two-piece ammunition.
Using the electrohydraulic turret traverse, the gunner could turn the turret at 18 degrees per second, with 15 degrees of elevation and 8 degrees of gun depression.
Secondary armament comprised a twin coaxial mount for cal.30 with 5250 rounds in store, the usual M2 cal.50 on the roof, at the extreme rear of the turret.
|Mass||65 short tons (58 long tons; 59 t)|
|Length||37 ft 2 in (11.33 m)|
|Width||12 ft 2 in (3.71 m)|
|Height||10 ft 6 in (3.20 m)|
|Crew||5 (commander, gunner, driver, 2 loaders)|
|Armor||127 mm (5 in) @ 60 degrees|
254 mm LoS (10 in)
|120 mm gun M58, 34 rounds|
|2×.30-cal (7.62 mm) M1919A4E1 machine gun|
1×.50-cal (12.7 mm) M2 AA machine gun
|Engine||(M103A1) Continental AV1790 12-cylinder air-cooled gasoline|
810 hp (604 kW)
(M103A2) Continental AVDS-1790-2, V12, air-cooled, twin turbocharged diesel
|Power/weight||M103A2: 12.7 hp (9.5 kW) / tonne|
|Transmission||General Motors CD-850-4A or -4B, 2 ranges forward, 1 reverse|
|Fuel capacity||280 US gallons (710 liters)|
|M103: 80 mi (130 km)|
M103A2: 295 mi (480 km)
|Maximum speed||M103: 21 mph (34 km/h)|
M103A2: 23 mph (37 km/h)