High Explosive Anti-tank Warhead - History

History

Shaped charge warheads were promoted internationally by the Swiss inventor Henry Mohaupt, who exhibited the weapon before the Second World War. Prior to 1939 Mohaupt had demonstrated his invention to British and French ordnance authorities. During the war the French communicated the technology to the U.S. Ordnance Department, who recognized the significance of Mohaupt's research and invited him to the U.S.A. He arrived there in October 1940 to work as a consultant on the Bazooka project, one of the first applications of the shaped charge. Independent secret development by the German group of Cranz, Schardin, and Thomanek led to the first documented use of shaped charges in warfare, in a 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. It is not even certain the German and Swiss groups were truly independent.

By mid-1940 Germany introduced the first HEAT round to be fired by a gun, the 7.5 cm fired by the Kw.K.37 L/24 of the Panzer IV tank and the Stug III self-propelled gun (7.5 cm Gr.38 Hl/A, later editions B and C). In mid-1941 Germany started the production of HEAT rifle-grenades, first issued to paratroopers and by 1942 to the regular army units (Gewehr-Panzergranate 40, 46 and 61), but as with the British soon turned to the integrated warhead-delivery systems: In 1943 the Püppchen, Panzerschreck and Panzerfaust were introduced. The Panzerfaust and Panzerschreck or 'tank terror' gave the German infantryman the ability to destroy any tank on the battlefield from 50-150m with relative ease of use and training (unlike the UK PIAT). The Germans also made use of large quantities of HEAT ammunition in converted 7.5 cm Pak 97/38 guns from 1941, later fabricating a HEAT warhead for the Mistel weapon. The latter weighed nearly two tons and was perhaps the largest HEAT warhead ever deployed. It was intended for use against heavily armoured warships, like battleships.

During World War Two the British referred to the Monroe effect as the cavity effect on explosives. The first British HEAT weapon to be developed and issue was a rifle grenade using a 2 1/2 inch cup launcher on the end of the barrel; the British No. 68 AT grenade issued to the British army in 1940. By 1943 the combination of HEAT warhead and spigot mortar delivery in the cumbersome PIAT weapon at last allowed British infantry to engage armour at ranges not bordering on suicide, about 115 yards; as was sometimes the case with magnetic hand-mines and grenades. The Germans came up with an effective counter to hollow-charged or HEAT weapons such as the PIAT or Bazooka through the use of armoured skirts or mesh skirts on their tanks, which caused the HEAT shell to detonate prematurely.

The need for a large bore made HEAT rounds relatively ineffective in existing small-caliber anti-tank guns of the era. The Germans were able to capitalize on this, however, introducing a round that was placed over the end on the outside of their otherwise obsolete 37 mm anti-tank guns to produce a medium-range low-velocity weapon.

Adaptations to existing tank guns were somewhat more difficult, although all major forces had done so by the end of the war. Since velocity has little effect on the armor-piercing capability of the round, which is defined by explosive power, HEAT rounds were particularly useful in long-range combat where the slower terminal velocities were not an issue. The Germans were again the ones to produce the most capable gun-fired HEAT rounds, using a driving band on bearings to allow it to fly unspun from their existing rifled tank guns. HEAT was particularly useful to them because it allowed the low-velocity large-bore guns used on their numerous assault guns to become useful anti-tank weapons as well. Likewise, the Germans, Italians, and Japanese had many obsolescent "infantry guns" in service (short-barreled, low-velocity artillery pieces capable of both direct and indirect fire and intended for infantry support, similar in tactical role to mortars; generally an infantry battalion had a battery of four or six). HEAT rounds for these old infantry guns made them semi-useful anti-tank guns, particularly the German 150 mm guns (the Japanese 70 mm and Italian 65 mm infantry guns also had HEAT rounds available for them by 1944 but they were not very effective).

The general public remained in the dark about shape charge warheads (i.e. they even believed that it was a new super secret explosive) until early 1945 when the US Army co-operated with the US monthly publication Popular Science on a large and detailed article on the subject. Most Americans were shocked to learn that even their enemies in World War Two had what the US Army referred to as shape charge warhead weapons. During World War Two, weapons using HEAT warheads were known as having a hollow charge or shape charge warhead.

HEAT rounds caused a revolution in anti-tank warfare when they were first introduced in the later stages of World War II. A single infantryman could effectively destroy any existing tank with a handheld weapon, thereby dramatically altering the nature of mobile operations. After the war HEAT became almost universal as the primary anti-tank weapon. HEAT rounds of varying effectiveness were produced for almost all weapons from infantry weapons like rifle grenades and the M203 grenade launcher, to larger dedicated anti-tank systems like the Carl Gustav recoilless rifle. When combined with the wire-guided missile, infantry weapons were able to operate in the long-range role as well. Anti-tank missiles altered the nature of tank warfare throughout the 1960s and into the 80s, and remain an effective system today.