The M4 Sherman, officially Medium Tank, M4, was the most numerous battle tank used by the United States and some other Western Allies in World War II. It proved to be reliable and mobile. In spite of being outclassed by German medium and heavy tanks late in the war, the M4 Sherman was cheaper to produce and available in greater numbers. Thousands were distributed through the Lend-Lease program to the British Commonwealth and Soviet Union. 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. One controversial feature, a one-axis gyrostabilizer was not precise enough to allow firing when moving but did help keep the reticle on-target, so that when the tank did stop to fire, the gun would be aimed in roughly the right direction. 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 1939–41. The M4 went on to be produced in large numbers. It spearheaded many offensives by the Western Allies after 1942. A similar vehicle was developed at the same time in Canada, the Ram tank, however greater Sherman production and availability meant that the Ram was never used in action as a tank (many were converted to self-propelled guns and 'Kangaroo' armoured personnel carriers).
When the M4 tank arrived in North Africa in 1942, it was superior to the lighter German long-barrel 50 mm-gunned Panzer III and short-barrel 75 mm-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 75 mm 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 manufactured, and significant investment in tank recovery and repair units allowed disabled vehicles being repaired and returned to service. These factors combined to give the Americans numerical superiority in most battles, and many infantry divisions were provided with M4s and tank destroyers. During the Normandy campaign, 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. A M4A3E8 variant was introduced, with improved suspension and a high-velocity 76 mm gun as used on the tank destroyers.
Post World War II the Sherman, often in updated versions, saw combat in many conflicts, including the Korean War, Arab-Israeli Wars, and the Indo-Pakistani War of 1965.