What if "MBT and Lights tanks" for a 1980 WW3?

Object 327, a self-propelled gun from the late 1970s that takes an entirely different approach and places its fully-rotating 152 mm gun outside the fighting compartment.

It was thought that by putting the gun on the outside, you’d eliminate the need for a massive and heavy turret, and you didn’t need to worry about gassing the crew with the gun’s combustion gasses.