Anti-tank gun

Bofors 37 mm anti-tank gun as used by several nations

Anti-tank guns (towed or self-propelled) are cannons or guns designed to destroy enemy armored vehicles^[1] normally from defensive positions. In order to penetrate vehicle armor they fire anti-tank ammunition^[2] from longer-barreled guns to achieve higher muzzle velocity than field artillery weapons, e.g. howitzers. The higher velocity, flatter trajectory ballistics provide terminal kinetic energy to penetrate the moving/static target's armor at a given range and contact's angle. Any field artillery cannon with barrel length 15 to 25 times longer than its caliber was able also to fire anti-tank ammunition, such as the Soviet A-19.

World War II

Prior to World War II few anti-tank guns had (or needed) calibers larger than 50 mm. Examples of guns in this class include the German 37 mm, US 37 mm (the largest gun able to be towed by the jeep), French 25 mm and 47 mm guns, British QF 2-pounder (40 mm), Italian 47 mm and Soviet 45 mm. All of these light weapons could penetrate the thin armor found on most pre-war and early war tanks.

German PaK 38 50-mm anti-tank gun

At the start of World War II many of these weapons were still being used operationally, along with a newer generation of light guns that closely resembled their WWI counterparts. After Soviet T-34 and KV tanks were encountered these guns were recognized as ineffective against sloped armor, with the German lightweight 37 mm gun quickly nicknamed the "tank door knocker" (German: Panzeranklopfgerät), for revealing its presence without penetrating the armor.

Germany quickly introduced more powerful anti-tank guns, some which had been in the early stages of development prior to the war. By late 1942 the Germans had an excellent 50-mm high-velocity design, while they faced the QF 6-pounder introduced in the North African Campaign by the British Army, and later adopted by the US Army. By 1943 Wehrmacht was forced to adopt still larger calibers on the Eastern Front, the 75 mm and the famous 88 mm guns. The Red Army used a variety of 45 mm, 57 mm, and 100 mm guns, as well as deploying general-purpose 76.2 mm and 122-mm guns in the anti-tank role. For the Invasion of Normandy the British QF 17 pounder, whose design had begun before the 6 pounder entered service, was produced that proved to be a highly effective anti-tank gun also used as a tank and tank destroyer gun.

Self-propelled anti-tank guns

A British Archer tank destroyer, based on the hull of a Valentine tank

As towed anti-tank cannon guns grew in size and weight, they became less mobile and more cumbersome to maneuver, and required ever larger gun crews, who often had to wrestle the gun into position while under heavy artillery and/or tank fire. As the war progressed, this disadvantage often resulted in the loss or destruction of both the antitank gun and its trained crew. This gave impetus to the development of the self-propelled, lightly armored "tank destroyer" (TD). The tank destroyer was usually based on the hull of existing tank designs, using either a gun integrated into the hull or a fully rotating turret much like that of a conventional tank. These self-propelled (SP) AT guns were first employed as infantry support weapons in place of towed antitank guns. Later, due to a shortage of tanks, TDs sometimes replaced the former in offensive armored operations.

Early German-designed tank destroyers, such as the Marder I, employed existing light French or Czech design tank chassis, installing an AT gun as part of an armored, turret-less superstructure. This method to reduced both weight and conversion costs. The Soviet Union later adopted this style of self-propelled anti-tank gun or tank destroyer. This type of tank destroyer had the advantage of a reduced silhouette, allowing the crew to more frequently fire from defilade ambush positions. Such designs were easier and faster to manufacture and offered good crew protection, though the lack of a turret limited the gun's traverse to a few degrees. This meant that if the TD became immobilized due to engine failure or track damage, it could not rotate its gun to counter opposing tanks, making it an easy target. This vulnerability was later exploited by opposing tank forces. Late in the war, it was not unusual to find even the largest and most powerful tank destroyer abandoned on the field after a battle, having been immobilized by a single high-explosive shell to the track or front drive sprocket.

US Army pre-war infantry support doctrines emphasized the use of tank destroyers with open-top fully rotating turrets, featuring less armor than the standard M4 Sherman tanks, but with more powerful cannon. A 76 mm long-barrel tank cannon was fitted to the M10 and M18 designs. Late in 1944, the M36 appeared, equipped with a 90 mm cannon. With rotating turrets and good combat maneuverability, American TD designs generally worked well, although their light armor was no match for enemy tank cannon fire during one on one confrontations. Another disadvantage proved to be the open, unprotected turret, and casualties from artillery fire soon led to the introduction of folding armor turret covers. Near the war's end, a change in official doctrine caused both the self-propelled tank destroyer and the towed antitank gun to fall from favor in U.S. service, increasingly replaced by conventional tanks or infantry level antitank weapons. Despite this change, the M36 tank destroyer continued in service, and was used in combat as late as the Korean War.

See also

• Anti-tank grenade
• Anti-tank warfare
• List of anti-tank guns
• Tank gun

References

Notes

1. OXFORD Advanced Lerner`s DICTIONARY opf Current English, NEW EDITION, Cornelsen & OXFORD, A S Hornby, 5th edition, page 42.
2. MILITÄRISCHES STUDIENGLOSAR ENGLISCH Teil II/ Teil III, Deutsch – Englisch, Abkürzung Begriff, Bundessprachenamt (Stand Januar 2001), page. 283, anti-tank ammunition.