Seeking to keep the tank out of public sight, Secretary of Defense Charles E. Wilson nixed an October 1953 exhibition for the American Ordnance Association at Aberdeen Proving Ground.

[8] In 1953, the Pentagon began to reverse the Truman administration's policy of a broad production base in favor of Wilson's "single, efficient producer" concept.

General Motors would also become heir to any additional T43 orders after Chrysler tank production wrapped up in June 1954.

[9] Testing was unsatisfactory, with the tanks failing to meet Continental Army Command's[clarification needed] standards and being put into storage in August 1955.

A House Government Operations subcommittee report in July 1957 called for the heavy tank program to be audited.

The Continental AV-1790 engine was placed at the rear of the tank, and produced a maximum output of 810 horsepower (600 kW) and 1,600 pound-feet (2,200 N⋅m) of torque, fed through a General Motors CD-850-4 two-speed transmission.

This presented a host of logistical problems for the vehicle, most prominently the extremely limited range of just 80 miles (130 km).

Though this was partially corrected with the introduction of the AV-1790-2 diesel unit, the M103 would remain cumbersome and fuel-thirsty for the majority of its service life.

The frontal hull glacis was a compound pike, welded at the center seam, with up to 10-inch (250 mm) thick armor at the front.

The turret was a massive single-piece cast design, fitted with heavily sloped 10-inch (250 mm) rolled-homogeneous armor.

With both loaders, the maximum firing rate of the gun was five rounds per minute, owing to the design of the two-piece ammunition.

In addition, the ammunition stowage was not convenient, repeated firing caused excess chamber erosion, and tracks were easily thrown.

[17] Although the later variants of the M1 Abrams main battle tank utilize the same caliber of main gun, 4.7 in (120 mm), the M103's cannon was a rifled gun firing a separate-loading round, in which the projectile was loaded into the breech, followed by a cartridge case consisting of a brass case, primer, and propellant in a fixed unit.