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It spend much of its production life under-gunned, the turret ring was not suitable for upgrading the gun for one, though I think there were 4 variants in weaponry. The PZ-III was superior in its way, the 3-man turret was adopted by many, for example. Perhaps common with all tanks but the side armour could be opened up with most weapons on the battlefield. It was a great tank, produced in large numbers.
The machines hull was provided for the more superior StuG Assault Gun, a lower profile nasty.