The Soviet Object 416 medium tank was developed at the Construction Bureau of Factory No. 75, starting in the fall of 1949. The blueprint was developed by March 1950. Because of technical problems with the turret, a working prototype was not ready until April 1952. Improvements were made and another prototype was built in the summer of 1953, but the vehicle never entered mass production.
Development of Object 416 started at Kharkov Plant no.75. The goal of the project was to create an entirely new tank; that would be protected as much possible while weighing as little as possible. The technical stage of the project was finished in 1950. The first prototype was built one year later. Preliminary tests revealed a number of defects, most of which had to do with drivetrain and suspension reliability.
The extremely low height of the vehicle, implemented so that the frontal silhouette was as small as possible. This also to allowed adequate armor protection to be achieved with using little steel as possible. However, this concept had a severe impact on crew operation – the tank was simply too small to do anything in! Since it proved practically impossible to drive the vehicle and fire the gun simultaneously, the work on the prototype was stopped and “Object 416″ was redesigned into a self-propelled gun, receiving an official designation of SU-100M.
In 1952, SU-100M passed the tests, but it was never adopted in service. The reason for this was that in most ways, the SU-100M was basically equal – and sometimes inferior – to the SU-100P, which was serially produced since 1952.
At that point, the project was canceled, and all further development was stopped.