The Panzer IV was designed as a Medium Tank for supporting infantry. The early versions, Ausf A to F1 were armed with a low velocity 75mm L24 gun, firing mainly explosive shells but did have limited anti-tank capability. The Panzer III was meant to be the main medium tank but as the war progressed it was found the the Panzer IV was more suitable for upgrading with bigger guns and more armour, so it became the German army's main tank until the end of the war. The F2 and G model were upgunned with a 75mm L43 gun, which was much better against armoured targets than the earlier gun and when introduced in 1942, could knock out most tanks in the world fairly easily. The last of the G models were upgunned again with a longer and more powerful 75mm L48 gun, which was based on the PAK 40 anti tank field gun. This gun was also carried by the final H and J models and was capable of knocking out all but the most heavily armoured tanks at most battefield ranges. Over 8000 Panzer IV tanks were built and served with German Army and SS Panzer Divisions.