The StuG III Ausf F was upgunned and fitted with the 7.5cm StuK 40 L/43. The new gun resulted in some being referred to as StuG 40. Later Ausf F were fitted with the longer 7.5cm StuK 40 L/48 gun which was more effective. The higher velocity gun transformed the StuG III from an infantry support vehicle to a tank destroyer. Between March and September around 366 Ausf F were built.