The M4 Sherman, officially the Medium Tank, M4, was the most numerous battle tank used by the United States and some other Western Allies including Britain during World War II. It proved to be reliable and mobile. In spite of being outclassed by heavier German heavy tanks late in the war, the Sherman was cheaper to produce and available in greater numbers. Thousands were distributed to the Allies, including the British Commonwealth and the Soviet Union, through the lend-lease program. The M4 was the second-most produced tank of the World War II era, after the Soviet T-34. Its role in its parent nation’s victory was comparable to that of the T-34. The tank was named after the American Civil War General William Tecumseh Sherman by the British.
The M4 Sherman evolved from the interim M3 Medium Tank, which had its main armament in a side sponson mount. The M4 retained much of the previous mechanical design but put the main 75 mm gun in a fully traversing turret, with a gyrostabilizer enabling the crew to fire with reasonable accuracy while the tank was on the move. The designers stressed mechanical reliability, ease of production and maintenance, durability, standardization of parts and ammunition in a limited number of variants, and moderate size and weight. These factors combined with M4 Sherman’s then-superior armor and armament outclassed German light and medium tanks of 1939 – 1941. It spearheaded many offensives by the Western Allies after 1942.
When the Sherman Tank arrived in North Africa in 1942, it was superior to the lighter German long-barrel 50mm-gunned Panzer III and short-barrel 75mm-gunned Panzer IV. For this reason, the US Army believed the M4 would be adequate to win the war, and no pressure was exerted for further tank development. Logistical and transport restrictions, such as limitations imposed by roads, ports, and bridges, also complicated the introduction of a more capable but heavier tank. Tank destroyer battalions using vehicles built on the M4 hull and chassis, but with open-topped turrets and more potent high-velocity guns, also entered widespread use in the American army. Even by 1944, most M4 Shermans kept their dual purpose 75mm M3. By 1944 and 1945, the M4 was inferior to German heavy tanks but was able to fight on with support from growing numbers of fighter-bombers and artillery pieces.
The relative ease of production allowed huge numbers of the M4 to be produced, and significant investment in tank recovery and repair units paid off with more disabled vehicles being repaired and returned to service. These factors combined to give the Americans numerical superiority in most battles, and many infantry divisions could be provided with their own M4s and tank destroyers. By this stage of the war, German panzer divisions were rarely at full strength, and some U.S. infantry divisions had more fully tracked armored fighting vehicles than the depleted German panzer divisions did, providing an advantage for the Americans. The Americans also started to introduce the M4A3E8 variant, with improved suspension and a high-velocity 76 mm gun as used on the tank destroyers.