with the T139 90 mm gun and featured a revolving eight-round cylindrical maga- zine mounted at a downward angle. The top round of the magazine was extract- ed to the rear, tilted upwards, and loaded into the gun. The type of round was select- able, and could either be armor-piercing, high explosive, or smoke. Despite being an autoloading design, the T69 still required a human loader, who topped off the maga- zine and oversaw the round selection. To ease maintenance, the roof of the turret was hinged and could be lifted to provide access to the loading system for services.
In theory, the T69’s autoloader could pro- vide 33 rounds per minute, but in practice it was prone to a high rate of mechanical issues and could only carry 35 rounds in total (in comparison, the standard M47 of the time could carry 71 rounds). On 11 February 1958, the T69 project was can- celed, though the Ordnance Technical Committee notes do remark that the de- velopment provided invaluable lessons for future autoloading concepts. Today, the lone 90 mm Gun Tank T69 is on display at the U.S. Army Armor & Cavalry Collec- tion’s Training Support Facility at Fort Benning, Georgia, where it is still re- searched from time to time by Army en- gineers learning about the development of autoloaders.
Robert Cogan is the curator of the U.S. Army Armor & Cavalry Collection, Fort Moore, Georgia. He medically retired as a captain after serving 10 years as an armor officer. He deployed to Iraq.
The T69 with its hinged turret roof opened. This was to ease maintenance of the autoloading and fire control systems.
A view of the turret interior through the opened roof. An optical range finder runs across the top of the compartment.
A diagram showing the layout of the autoloader’s eight-round magazine underneath the gun breech. Spent rounds were ejected out of a port on the rear of the turret.
The firing end of the T139 90 mm gun. Later standardized as the M41, it was used on the M48-series of tanks.
A view of the rear of the T69,
showing the spent round ejection port on the back of the turret.
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A close-up of the ejection port. The Rheem Manufacturing Company’s name can be seen just below the port.
CAVALRY & ARMOR JOURNAL Spring 2026
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