The first model to emerge from the programme was the M3 medium tank – designated “Lee” by the U.S. Army and “Grant” by the British Army – a combat vehicle with several notable features in terms of armour, mobility, crew comfort, and firepower. However, it was limited by a rushed design and development process which, among other drawbacks, resulted in an excessively tall silhouette and a 75mm main gun mounted in the hull, requiring the entire vehicle to be turned in order to aim.
Impressed by the Blitzkrieg tactics witnessed during the 1940 Battle of France, the Americans began to develop a series of improvements based on the reliable hull and mechanical layout of the M3. The U.S. Armored Forces Board selected a new model, the M4, to become the standard medium tank of the future. It featured a turret-mounted main gun and was capable of outperforming the German PzKpfw III and PzKpfw IV tanks encountered in the 1940 campaigns.
From the outset, the M4 was intended for mass production on the same assembly lines that were already delivering hundreds of M3 tanks. It remained as close as possible to its predecessor, retaining the same running gear, suspension, rubber-padded tracks, engine, and transmission. However, it introduced a newly designed turret and hull – either welded or cast, depending on the version – representing a clear step forward from the riveted hull of the M3.
The initial engine used was the Wright R-975 Whirlwind, licence-built by Continental. Originally developed for aviation, it was a robust and versatile air-cooled petrol radial engine producing 400 hp at 2,400 rpm. Fuelled by two 660-litre tanks, it gave the vehicle a rather limited range due to high consumption, averaging around 450 litres per 100 kilometres. The first Shermans with radial engines were split into two versions: the M4 with a welded hull and the M4A1 with a cast hull.
These were followed by the M4A2, also with a welded hull, which differed primarily through the adoption of two Detroit Diesel 6-71 inline six-cylinder engines.
Supplied to the British Army in all three variants, the Sherman made its combat debut during the Second Battle of El Alamein in 1942. It immediately proved itself to be fast, well-armoured, and well-armed, with its 75mm M2 gun capable of defeating all Italian and German tanks fielded at the time. The promising results seemed to validate the American bet on a tank that was mechanically reliable, easy to produce, and practical to operate – benefiting from the practical expertise of the U.S. automobile industry, then the most advanced in the world.
However, only a few months later, during the North African landings of Operation Torch, American M4A1 units would receive a nasty surprise when they came up against a battered but seasoned and tenacious enemy, newly re-equipped with the long-barrelled 75mm Panzer IVs (PzKpfw IV Ausf F2 and Ausf G) and the fearsome Tiger I (PzKpfw VI), mounting the unmatched 88mm gun. Unexpectedly, U.S. forces lost dozens of Shermans in their first encounters with the Afrika Korps. With equipment evolving rapidly, the M4 soon lost its technical edge, though it remained a solid tank – arguably the best and certainly the most numerous fielded by the Western Allies in 1943. It became the principal Allied tank during the Sicily landings and the subsequent Italian campaign.
Furthermore, with 2,000 tanks being produced each month from mid-1942 onwards, the M4 was available in large numbers. In addition to the U.S. Army, Shermans were also supplied to the Soviet and British forces (designated M4, M4A1 and M4A2, or Sherman I, II, and III in British nomenclature). The Soviets received the M4A2 with its welded hull and diesel-powered Detroit engines – a key logistical advantage for the Eastern Front. While Soviet crews appreciated the Sherman’s reliability and relative comfort, they generally considered it inferior to their own T-34/76, which offered better armour and was better suited to the extreme conditions of the Eastern Front.
The Sherman’s greatest trial would come during Operation Overlord and the Normandy landings. It was then that the M4 faced its toughest challenge, coming up against the latest German tanks, which in many respects were technically superior to the M4A1 and M4A2 variants most commonly fielded by the Allies.
Having studied a captured Tiger I in Tunisia, the British, ever pragmatic, developed the Firefly variant in time for D-Day. Based on existing Sherman hulls, the Firefly was fitted with the powerful 17-pounder (76.2mm) QF gun, capable of matching the German tanks’ firepower. On D-Day, around 500 Fireflies were available – roughly one in five British Shermans – and they immediately became priority targets for German gunners due to the threat they posed. Meanwhile, based on their own combat experience, the Americans had just begun producing a version of the Sherman with a longer 76mm gun offering markedly better performance than the original 75mm piece, which still equipped the vast majority of armoured divisions in the early weeks after the landings.
Ultimately, the Shermans prevailed through sheer weight of numbers and overwhelming air support from USAAF P-47 Thunderbolts and P-38 Lightnings, and RAF Hawker Typhoons – though at a heavy cost. U.S. command was reportedly willing to lose five Shermans in order to outflank and destroy a single German Panther. Of course, crews were unaware of this grim statistic, and high command did not prioritise the immediate deployment of 76mm-armed tanks, which would only become widespread in the final months of the war – as would the new Sherman variant with wider tracks and HVSS suspension.
This final version addressed much of the significant qualitative gap in tank design experienced during the Allied push through Europe, and was particularly appreciated by Soviet crews, as it combined the Sherman’s legendary reliability with an effective main gun and wide tracks better suited to the snow and mud typical of the Eastern Front.
Across all variants, a total of 49,630 Sherman tanks were produced. Thousands of surviving examples were supplied to Allied nations after the war and remained in service for many years. As a result, they participated in nearly every post-war conflict – from the Chinese Civil War, which lasted until 1949, to the collapse of the South Lebanon Army in 2000, when the final veteran and heavily modified M-50 Shermans were returned to Israel, closing a remarkable 58-year chapter of active combat service.