Tanks are armoured fighting vehicles designed for front-line combat, combining operational mobility and tactical offensive and defensive capabilities; tanks perform all primary tasks of the armoured troops. The tank destroyer on the other hand is specifically designed to take on enemy tanks and other armoured fighting vehicles. Many are based on a tracked tank chassis, while others are wheeled.
The first German tank destroyers were the Panzerjäger ("tank hunters"), which mounted an existing anti-tank gun on a convenient chassis for mobility, usually with just a three-sided gun shield for crew protection. For instance, 202 obsolete Panzer I light tanks were modified by removing the turret and were rebuilt as the Panzerjäger I self-propelled 4.7 cm PaK(t). Similarly, Panzer II tanks were used on the eastern front. Captured Soviet 76.2 mm anti-tank guns were mounted on modified Panzer II chassis, producing the Marder II self-propelled anti-tank gun. The most common mounting was a German 75 mm anti-tank gun on the Czech Panzer 38(t) chassis to produce the Marder III. The Panzer 38(t) chassis was also used to make the Jagdpanzer 38 casemate style tank destroyer. The Panzerjäger series continued up to the 88 mm equipped Nashorn.
Since World War 2, gun-armed powerful tank destroyers have fallen out of favor as armies have favored multirole main battle tanks. However, lightly armored anti-tank guided missile (ATGM) carriers are commonly used for supplementary long-range anti-tank work. The resurgence of expeditionary warfare in the first two decades of the 21st century has seen the emergence of gun-armed wheeled vehicles, sometimes called protected gun systems, which may bear a superficial resemblance to tank destroyers, but are employed as direct fire support units typically providing support in low-intensity operations such as the wars in Iraq and Afghanistan.
