Comparing: Centurion Action X vs. 121B

The Action X turret was planned to be used for later variants of the Centurion tank. One prototype of the turret was mounted on the chassis of the Centurion Mark 7, and another was used for ballistic trials. The vehicles with the Action X turret never entered mass production or saw service.

The upgraded version of the 121 Chinese medium tank, developed in the 1960s. Unlike the prototype, the 121B was equipped with a modern 105-mm rifled gun, improved suspension, and reinforced front armor. The vehicles of this modification were equipped with infrared lamps and a laser rangefinder. The 121B aiming system had a higher firing accuracy than that of the Type 59.