Medium Tanks M2, M2A1, and T5

Having repeatedly failed to design a new medium tank , the US Army decided to start over with a new design, leading to the M2 Medium Tank.

Light Tank T21

The US Army was interested in replacing the Stuart light tanks, however, with the failure of the M7, the T21 Light Tank project was started.

Heavy Tank M6A2E1

The Heavy Tank M6A2E1 was a project to mount the main gun and turret of the prototype T29 heavy tank on the hull of an M6 heavy tank.