Panzer I it still performed much useful service against entrenched infantry and other "soft" targets, which were unable to respond even against thin armor, and who were highly vulnerable to machine gun fire. The small, vulnerable light tank, along with its somewhat more powerful successor the Panzer II, would soon be surpassed as a front-line armoured combat vehicle by more powerful German tanks, such as the Panzer III, and later the Panzer IV, Panzer V, and Panzer VI; nevertheless, the Panzer I's contribution to the early victories of Nazi Germany during World War II was significant. Later in that war the turrets
Panzer IV enclosed turret armed with twin Rheinmetall-Borsig MK 103 aircraft autocannon. Although not a direct modification of the Panzer IV, some of its components, in conjunction with parts from the Panzer III, were utilized to make one of the most widely used self-propelled artillery chassis of the war—the Geschützwagen III/IV. This chassis was the basis of the "Hummel" artillery piece, of which 666 were built, and also the gun-armed Nashorn tank destroyer, with 473 manufactured. To resupply self-propelled howitzers in the field, 150 ammunition carriers were manufactured on the Geschützwagen III/IV chassis. Another rare variant was the "Bergepanzer" IV armored recovery