M103: The Tank With No Name

In 1950, the USA was facing a tank crisis… and the M103 was supposed to be part of the solution. But it would hardly ever be used.

After the Second World War, the USA made massive cuts to their conventional forces – declaring the majority of their tanks obsolete, with those left coming to the end of their service life. And the appearance of the Soviet IS-3 meant that the pressure was on. The US Army and the US Marine Corps wanted new tanks – and they wanted them fast. And the appearance of the Soviet IS-3 meant that the pressure was on. The USA declared a “Tank Crisis”.

The T-43 heavy tank was intended to be the response to new Soviet armour. But vehicles were being built before the bugs had been ironed out – and the delays began to mount up. Whilst the Army began to question the need for a heavy tank, the Marines went all in on the concept – ordering over 200 for their forces. But the T-43 was nowhere near ready to enter service, and the vehicles went into storage with 114 improvements needed.

Changes were made and eventually the Marines got their heavy tank – now named the M103. But its effectiveness was limited, and the M103 was only operationally deployed once. The Marines rejected replacement M60s in favour of the Future Main Battle Tank – a project that would end up being cancelled. Their existing M103AA1s were modernised using M60 parts, creating the M103A2 – which The Tank Museum has an example of in its running fleet.

The M103 is a heck of a tank: powerful, capable and incredibly imposing to be around. But did the Americans really need it? Was it the ultimate panic buy?

This is the story of the M103 Heavy Tank – and the panic that produced it.

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This video features archive footage courtesy of British Pathé. This video features archive material courtesy of the US Army Armor and Cavalry Collection.

In this film, the museum’s Historian and Presenter – Chris Copson – explores the history of the ultimate panic buy: the M103. In the 1950s, war was brewing, and the US Army was running short of tanks. The race was on to build new tanks that could take on the IS-3 – the Soviet’s latest heavy armour. But the rush to get these tanks ready meant overlooking significant flaws that caused problems in service. While the Marines clung to the M103, the heavy tank was only deployed once – to the US base at Guantanamo Bay. The M103 remains a fascinating piece of Cold War history and a prime example of buyers’ remorse.

Want to learn more about the M103? Here are some of the sources we used to make this film:

AFV Database

Firepower – A History of the American Heavy Tank. Richard P. Hunnicutt, 1988

History of Acquisition in the Department of Defence. Volume IRearming for the Cold War 19451960. Elliott V. Converse III, 2012. Historical OfficeOffice of the Secretary of Defence

M103 Heavy Tank 1950-74. Osprey New Vanguard 197. Kenneth W. Estes, 2012

Marines Under Armor: The Marine Corps and the Armored Fighting Vehicle, 1916-2000. Kenneth W. Estes, 2000

United States Marine Corps Film Repository (University of South Carolina)

US Battle Tanks 1946-2025. Steven J. Zaloga, 2025

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