With the debut of the Panther in 1943 the Pz.Kpfw.III and Pz.Kpfw.IV were threatened with cancellation. Their chassis would be used to make StuGs, a vehicle that could not be replaced with the Panther. However, Guderian himself wrote a treatise in defense of the humble Pz.Kpfw.IV.
"Notes for the Fuhrer's report (September 5th, 1943)
Pz.Kpfw.IV tank or assault gun?
Despite arriving reports, the assault gun has practically no advantages over the Pz.Kpfw.IV tank, as the assault gun:
- ...lacks a rotating turret and therefore acts in one direction, forwards, having to turn in its entirety in order to engage targets on its flanks or behind it, which takes a lot of time (24 degrees compared to 360 degrees).
- ...is defenseless against attacks at close range (there is no machine gun installed) and therefore requires constant infantry cover (see also instructions for artillery troops when using assault guns).
- ...has somewhat poorer mobility (weighs 1.5 tons more than a Pz.Kpfw.IV tank).
These tactical and technical drawbacks of the assault gun are in no way made up for by its advantages over the Pz.Kpfw.IV tank (low height, 80 mm thick front armour vs 50 mm). The assault gun is incapable of acting rapidly and decisively in all directions and cannot fight without support from other forces when necessary. The Pz.Kpfw.IV tank can do all of this.
If the situation demands it, the Pz.Kpfw.IV tank can be used as an assault gun, but an assault gun can never be used as a tank.
Ceasing Pz.Kpfw.IV production would make a multidirectional weapon into a unidirectional weapon.
Reports from the front line that speak of the assault gun's superiority over the Pz.Kpfw.IV are subjective. An assault gun remains with its infantry and the tank is often taken away for other tasks. Because of this, greater sympathy is developed for the assault gun.
It would be impossible to reverse a changeover or especially an inevitable general increase in production if it would later become necessary to do so.
I propose this: do not change production in any way, on the contrary, introduce tanks into battle to complete the task of assault guns when necessary."