Comparing: AC 4 Experimental vs. Pz.Kpfw. IV Schmalturm

The tank was developed in 1943. An order was placed for 400 vehicles. The prototype was created on the basis of the AC 1 tank with an enlarged superstructure, which allowed mounting a modified turret from the AC 3 tank with a 17-pounder gun. In July 1943, the work on the project was stopped at the final stage, as the program for creating the Australian cruiser tank was discontinued.

In November 1944 the Krupp company presented several avant-projects aimed to upgrade armament of tanks and tank destroyers in service. Among them there was a project of mounting a Panther's Schmalturm (tight turret) on the Pz IV Ausf. J. The project was canceled due to phasing out the Pz IV production.