Before the start of Operation Barbarossa, the decision was taken to improve the anti-tank capabilities of the Pz.Kpfw. IV by mounting the 50 mm Kw.K. L/60 cannon. However, battles against the Soviet T-34 and KV tanks during the summer-fall campaign of 1941 showed that it needed a much more potent gun. The 75 mm Kw.K. 40 L/43 with its prominent pear-shaped muzzle break was used as a replacement. This gun's armor-piercing shells could easily penetrate any mass-produced tank of that period from distances of over 1.5 km.