 The Pak 39 was an electrically fired weapon fitted with a semi-automatic breech mechanism and a 48 caliber long barrel.The gun was able to destroy the most common allied tanks at up to 1,000 meters.It used the same 75 x 495R ammunition as the 7.5 cm KwK 40 of Panzer IV and 7.5 cm StuK 40 gun fitted on the "Sturmgeschütz" assault guns.