Anti-tank guns are a form of artillery designed to destroy armored fighting vehicles, normally from static defensive positions. The development of specialized anti-tank munitions and anti-tank guns was prompted by the appearance of tanks during World War I. To destroy hostile tanks, artillerymen often used field guns depressed to fire directly at their targets. However, this practice expended too much valuable ammunition and was of increasingly limited effectiveness as tank armor became thicker. The first dedicated anti-tank artillery began appearing in the 1920s and by World War II was a common appearance in many European armies. In order to penetrate armor they fired specialized ammunition from longer barrels to achieve a higher muzzle velocity than field guns. Most anti-tank guns were d