German Army 15. Krupp Sd.Kfz.161 Panzer IV J Over 6,000 examples of Panzerkampfwagen IV tanks were produced between 1943 and 1945. After the appearance of the Russian T-34-with its dominant guns and heavier, sloped armor-the Panzer needed design modifications such as thick side and turret skirts, a new gun (the KwK 40 75mm L/48) and a larger turret.