High explosive antitank

A high-explosive anti-tank (HEAT) warhead is a type of shaped charge explosive that uses the Munroe effect to penetrate armor. The warhead functions by having the explosive charge melt a metal liner to form a high-velocity superplastic jet. This concentrated metal jet is capable of penetrating armor steel to a depth of seven or more times the diameter of the charge (charge diameters, CD). Contrary to a widespread misconception (possibly resulting from the acronym HEAT), the jet does not melt its way through armor, as its effect is purely kinetic in nature. The HEAT warhead has become less effective against tanks and other armored vehicles due to the use of composite armour and explosive-reactive armor.

HEAT warheads were developed during World War II, from extensive research and development into shaped charge warheads.

Shaped charge warheads were promoted internationally by the Swiss inventor Henry Mohaupt, who exhibited the weapon before World War II. Before 1939, Mohaupt demonstrated his invention to British and French ordnance authorities. Concurrent development by the German inventors group of Cranz, Schardin, and Thomanek led to the first documented use of shaped charges in warfare, during the successful assault on the fortress of Eben Emael on 10 May 1940.

Claims for priority of invention are difficult to resolve due to subsequent historic interpretations, secrecy, espionage, and international commercial interest.

The first British HEAT weapon to be developed and issued was a rifle grenade using a 63.5 millimetres (2.50 in) cup launcher on the end of the rifle barrel; the Grenade, Rifle No. 68 /AT which was first issued to the British Armed Forces in the year 1940. This has some claim to have been the first HEAT warhead and launcher in use. The design of the warhead was simple and was capable of penetrating 52 millimetres (2.0 in) of armour. The fuze of the grenade was armed by removing a pin in the tail which prevented the firing pin from flying forward. Simple fins gave it stability in the air and, provided the grenade hit the target at the proper angle of 90 degrees, the charge would be effective. Detonation occurred on impact, when a striker in the tail of the grenade overcame the resistance of a creep spring and was thrown forward into a stab detonator.

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