High explosive anti-tank
High explosive anti-tank (HEAT) warheads are made of an explosive shaped charge
Shaped charge
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...

 that uses the Munroe effect to create a very high-velocity partial stream of metal in a state of superplasticity
In materials science, superplasticity is a state in which solid crystalline material is deformed well beyond its usual breaking point, usually over about 200% during tensile deformation. Such a state is usually achieved at high homologous temperature, typically half the absolute melting point. ...

 that can punch through solid armor
Vehicle armour
Military vehicles are commonly armoured to withstand the impact of shrapnel, bullets, missiles, or shells, protecting the personnel inside from enemy fire. Such vehicles include tanks, aircraft, and ships....


Contrary to a widespread misconception perpetuated by the acronym, HEAT rounds do not depend in any way on thermal phenomena for their effectiveness. In particular, the shaped charge jets do not "melt their way" through armor, only reaching 500-600°C, and instead rely on extreme pressure to force a hole through the armor. The confusion about rounds "melting their way" through armor has arisen from the acronym HEAT, as well as early descriptions of how the weapons worked, including the first manuals for the M72 LAW
The M72 LAW is a portable one-shot 66 mm unguided anti-tank weapon, designed in the United States by Paul V. Choate, Charles B. Weeks, and Frank A. Spinale et al...

 officially issued at the start of the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...



The stream moves at hypersonic
In aerodynamics, a hypersonic speed is one that is highly supersonic. Since the 1970s, the term has generally been assumed to refer to speeds of Mach 5 and above...

 speeds (up to 25 times the speed of sound
Speed of sound
The speed of sound is the distance travelled during a unit of time by a sound wave propagating through an elastic medium. In dry air at , the speed of sound is . This is , or about one kilometer in three seconds or approximately one mile in five seconds....

) in solid material and therefore erodes exclusively in the contact area of jet and armor material. The correct detonation point of the warhead and spacing is critical for optimum penetration, for two reasons:
  1. If the HEAT warhead is detonated too close to the target's surface there is not enough time for the particle stream to fully develop. That is why most modern HEAT warheads have what is called a "standoff", in the form of an extended nose cap or probe in front of the warhead.Both the US TOW and the French-German MILAN wire guided antitank missiles almost doubled their maximum penetration by the addition of a standoff probe.
  2. The distance is critical because the stream disintegrates and disperses after a relatively short distance, usually well under 2 metres. The stream material is formed by a cone of metal foil lining, usually copper
    Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...

    , though ductile iron and tin
    Tin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...

     foil was commonly used during the Second World War.

The key to the effectiveness of a HEAT round is the diameter of the warhead
The term warhead refers to the explosive material and detonator that is delivered by a missile, rocket, or torpedo.- Etymology :During the early development of naval torpedoes, they could be equipped with an inert payload that was intended for use during training, test firing and exercises. This...

. As the penetration continues through the armor, the width of the hole decreases leading to a characteristic "fist to finger" penetration, where the size of the eventual "finger" is based on the size of the original "fist". In general, very early HEAT rounds can expect to penetrate armor of 150% to 250% of their diameter, and these numbers were typical of early weapons used during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. Since the Second World War, the penetration of HEAT rounds relative to projectile diameters has steadily increased as a result of improved liner material and metal jet performance. Some modern examples claim numbers as high as 700%.

HEAT projectile stabilization and accuracy

HEAT warheads become much less effective if they are rapidly spinning, which became a challenge for weapon designers – for a long time, spinning the shell was the most standard method for obtaining good accuracy, as with any rifled
Rifling is the process of making helical grooves in the barrel of a gun or firearm, which imparts a spin to a projectile around its long axis...

 gun. But the centrifugal force
Centrifugal force
Centrifugal force can generally be any force directed outward relative to some origin. More particularly, in classical mechanics, the centrifugal force is an outward force which arises when describing the motion of objects in a rotating reference frame...

 disperses the charge jet, consequently most hollow charge projectiles are fin-stabilised and not spin-stabilised. The round could be fired from smoothbore
A smoothbore weapon is one which has a barrel without rifling. Smoothbores range from handheld firearms to powerful tank guns and large artillery mortars.-History of firearms and rifling:...

 barrel, losing some accuracy.

In recent years it has become possible to use shaped charges in spin-stabilised projectiles by imparting an opposite spin on the jet so that the two spins cancel out and result in a non-spinning jet. This is done either using fluted copper liners, which have raised ridges or by manufacturing the liner in such a way that it has a crystalline structure which itself imparts a spin on the jet.

Besides spin-stabilisation, another problem with any barreled weapon (that is, a gun) is that large-diameter shell has worse accuracy than small-diameter shell of the same weight. The lessening of accuracy increases dramatically with range. Paradoxically, this leads to situation when a kinetic
Kinetic energy
The kinetic energy of an object is the energy which it possesses due to its motion.It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acceleration, the body maintains this kinetic energy unless its speed changes...

 armor-piercing projectile is more usable at long ranges than a HEAT projectile, despite the latter having a higher armor penetration. To illustrate this: a stationary Soviet T-62
The T-62 is a Soviet main battle tank, a further development of the T-55. Its 115 mm gun was the first smoothbore tank gun in use.The T-62 was produced between 1961 and 1975. It became a standard tank in the Soviet arsenal, partly replacing the T-55, although that tank continued to be...

 tank, firing from (smoothbore) cannon at a range of 1000 meters against a target moving 19 km/h, was rated to have a first-round hit probability of 70% when firing a kinetic (APFSDS) projectile. Under the same conditions, it could expect 25% when firing HEAT round. This affects combat on open battlefield with long lines of sight; the same T-62 could expect a 70% first-round hit probability using HEAT rounds on target at 500 meters.

A further problem is that, if the warhead is contained inside the barrel, its diameter becomes overly restricted by the caliber
In guns including firearms, caliber or calibre is the approximate internal diameter of the barrel in relation to the diameter of the projectile used in it....

 of that barrel. In non-gun applications, when HEAT warhead is delivered with missile
Though a missile may be any thrown or launched object, it colloquially almost always refers to a self-propelled guided weapon system.-Etymology:The word missile comes from the Latin verb mittere, meaning "to send"...

s, rocket
A rocket is a missile, spacecraft, aircraft or other vehicle which obtains thrust from a rocket engine. In all rockets, the exhaust is formed entirely from propellants carried within the rocket before use. Rocket engines work by action and reaction...

s, bomb
A bomb is any of a range of explosive weapons that only rely on the exothermic reaction of an explosive material to provide an extremely sudden and violent release of energy...

s, grenade
A grenade is a small explosive device that is projected a safe distance away by its user. Soldiers called grenadiers specialize in the use of grenades. The term hand grenade refers any grenade designed to be hand thrown. Grenade Launchers are firearms designed to fire explosive projectile grenades...

s, or spigot mortars, the warhead size is no longer a limiting factor. In these cases HEAT warhead often seems oversized in relation to the round's body. Classic examples to illustrate this include the German Panzerfaust
The Panzerfaust was an inexpensive, recoilless German anti-tank weapon of World War II. It consisted of a small, disposable preloaded launch tube firing a high explosive anti-tank warhead, operated by a single soldier...

 and Soviet RPG-7
The RPG-7 is a widely-produced, portable, unguided, shoulder-launched, anti-tank rocket-propelled grenade launcher. Originally the RPG-7 and its predecessor, the RPG-2, were designed by the Soviet Union, and now manufactured by the Bazalt company...



Shaped charge
Shaped charge
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...

 warheads were promoted internationally by the Swiss inventor Henry Mohaupt, who exhibited the weapon before the Second World War
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

. 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
Bazooka is the common name for a man-portable recoilless rocket antitank weapon, widely fielded by the U.S. Army. Also referred to as the "Stovepipe", the innovative bazooka was amongst the first-generation of rocket propelled anti-tank weapons used in infantry combat...

 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
Panzer IV
The Panzerkampfwagen IV , commonly known as the Panzer IV, was a medium tank developed in Nazi Germany in the late 1930s and used extensively during the Second World War. Its ordnance inventory designation was Sd.Kfz...

 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 paratrooper
Paratroopers are soldiers trained in parachuting and generally operate as part of an airborne force.Paratroopers are used for tactical advantage as they can be inserted into the battlefield from the air, thereby allowing them to be positioned in areas not accessible by land...

s and by 1942 to the regular army units (Gewehr-Panzergranate 40, 46 and 61), but as with the British soon turned to the integrate warhead-delivery systems: In 1943 the Püppchen, Panzerschreck
Panzerschreck was the popular name for the Raketenpanzerbüchse , an 88 mm calibre reusable anti-tank rocket launcher developed by Nazi Germany in World War II. Another popular nickname was Ofenrohr ....

and Panzerfaust
The Panzerfaust was an inexpensive, recoilless German anti-tank weapon of World War II. It consisted of a small, disposable preloaded launch tube firing a high explosive anti-tank warhead, operated by a single soldier...

were introduced. The Germans also made use of large quantities of HEAT ammunition in converted 7.5 cm Pak 97/38
7.5 cm PaK 97/38
The Pak 97/38 was a German anti-tank gun used by the Wehrmacht in World War II. The gun was a combination of the barrel from the French Canon de 75 modèle 1897 and the carriage of the German 5 cm Pak 38....

 guns from 1941, later fabricating a HEAT warhead for the Mistel
The Mistel , also known as Beethoven-Gerät and Vati und Sohn , was a Luftwaffe composite aircraft type of bomber, that appeared late in World War II....

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, for example 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 1942 the combination of HEAT warhead and spigot mortar delivery in the PIAT
The Projector, Infantry, Anti Tank was a British hand-held anti-tank weapon developed during the Second World War. The PIAT was designed in 1942 in response to the British Army's need for a more effective infantry anti-tank weapon, and entered service in 1943.The PIAT was based on the spigot...

 weapon at last allowed British infantry to engage armour at ranges not bordering on suicide, as was sometimes the case with magnetic hand-mines and grenades.

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. A more convincing system was created by making a much larger tripod-mounted version of the Panzerschreck, producing the 7.5 cm Leichtgeschütz 40
7.5 cm Leichtgeschütz 40
The 7.5 cm Leichtgeschütz 40 was a recoilless gun used by the German Army during World War II.-Background:Development of recoilless weapons by Rheinmetall began in 1937 in an effort to provide airborne troops with heavy support weapons that could be dropped by parachute. Both Krupp and...

, what is today known as a recoilless rifle
Recoilless rifle
A recoilless rifle or recoilless gun is a lightweight weapon that fires a heavier projectile than would be practical to fire from a recoiling weapon of comparable size. Technically, only devices that use a rifled barrel are recoilless rifles. Smoothbore variants are recoilless guns...

. The recoilless rifle had the range to stay easily hidden on the battlefield, was light enough to be portable by a small team, but had the performance needed to defeat any tank. The main drawbacks were a short range and a large back blast that gave the weapon's position away when fired.

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
Driving band
The driving band or rotating band is part of an artillery shell, a band of soft metal near the middle of the shell, typically made of gilding metal, copper or lead...

 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 gun
Assault gun
An assault gun is a gun or howitzer mounted on a motor vehicle or armored chassis, designed for use in the direct fire role in support of infantry when attacking other infantry or fortified positions....

s 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
Mortar (weapon)
A mortar is an indirect fire weapon that fires explosive projectiles known as bombs at low velocities, short ranges, and high-arcing ballistic trajectories. It is typically muzzle-loading and has a barrel length less than 15 times its caliber....

; 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
Type 92 Battalion Gun
The was a light howitzer used by the Imperial Japanese Army during the Second Sino-Japanese War and World War II. Each infantry battalion included two Type 92 guns; therefore, the Type 92 was referred to as .-History and development:...

 and Italian 65 mm
65 mm mountain gun
The cannone da 65/17 modello 13 was an artillery piece developed by Italy for use with its mountain and infantry units. The designation means 65 mm calibre gun, barrel length 17 calibres, which entered service in 1913...

 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
Popular Science
Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...

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 grenade
Rifle grenade
A rifle grenade is a grenade that uses a rifle-based launcher to permit a longer effective range than would be possible if the grenade was thrown by hand...

s and the M203
M203 grenade launcher
The M203 is a single shot 40 mm grenade launcher designed to attach to a rifle. It uses the same rounds as the older M79 break-action grenade launcher, which utilize the High-Low Propulsion System to keep recoil forces low. Though versatile, and compatible with many rifle models, the M203 was...

 grenade launcher
Grenade launcher
A grenade launcher or grenade discharger is a weapon that launches a grenade with more accuracy, higher velocity, and to greater distances than a soldier could throw it by hand....

, to larger dedicated anti-tank systems like the Carl Gustav recoilless rifle
Carl Gustav recoilless rifle
The Carl Gustav is the common name for the 84 mm man-portable reusable multi-role recoilless rifle produced by Saab Bofors Dynamics in Sweden...

. When combined with the wire-guided missile
Wire-guided missile
A wire-guided missile is a missile that is guided by signals sent to it via thin wires connected between the missile and its guidance mechanism, which is located somewhere near the launch site. As the missile flies, the wires are reeled out behind it...

, 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.

Helicopter armament

Helicopters have also carried anti-tank guided missiles (ATGM) tipped with HEAT warheads since the early 1960s. The first example of this was the use of the Nord SS.11 ATGM on the Aérospatiale Alouette II helicopter by the French armed forces. Subsequently, such antitank-capable helicopters were widely adopted by other nations.

On April 13, 1972, Chief Warrant Officer
Chief Warrant Officer
Chief warrant officer is a military rank used by the Canadian Forces and the Israel Defence Forces.-Canada:In the Canadian Forces, a chief warrant officer or CWO is the most senior non-commissioned member rank in the Canadian Army and the Royal Canadian Air Force...

 Barry McIntyre, Major
Major is a rank of commissioned officer, with corresponding ranks existing in almost every military in the world.When used unhyphenated, in conjunction with no other indicator of rank, the term refers to the rank just senior to that of an Army captain and just below the rank of lieutenant colonel. ...

 Larry McKay, First Lieutenant
First Lieutenant
First lieutenant is a military rank and, in some forces, an appointment.The rank of lieutenant has different meanings in different military formations , but the majority of cases it is common for it to be sub-divided into a senior and junior rank...

 Steve Shields, and Captain Bill Causey became the first helicopter crews to destroy enemy armour
Armoured warfare
Armoured warfare or tank warfare is the use of armoured fighting vehicles in modern warfare. It is a major component of modern methods of war....

 in combat during the Vietnam War
Vietnam War
The Vietnam War was a Cold War-era military conflict that occurred in Vietnam, Laos, and Cambodia from 1 November 1955 to the fall of Saigon on 30 April 1975. This war followed the First Indochina War and was fought between North Vietnam, supported by its communist allies, and the government of...

. A flight of two Cobra helicopters
AH-1 Cobra
The Bell AH-1 Cobra is a two-bladed, single engine attack helicopter manufactured by Bell Helicopter. It shares a common engine, transmission and rotor system with the older UH-1 Iroquois...

 from Battery F, 79th Artillery
Aerial Rocket Artillery
Although sometimes used as a generic term for any armed helicopters, the term Aerial Rocket Artillery refers specifically to the armed helicopter units which were organic to the division artillery of the United States Army’s two airmobile divisions during the Vietnam War...

, 1st Cavalry Division, U.S. Army
United States Army
The United States Army is the main branch of the United States Armed Forces responsible for land-based military operations. It is the largest and oldest established branch of the U.S. military, and is one of seven U.S. uniformed services...

, were armed with the newly developed 2.75" HEAT rockets, which were yet untested in combat. The specially modified Huey which was shipped in an emergency destroyed three T-54 tanks that were about to overrun a U.S. command post. McIntyre and McKay engaged first, destroying the lead tank.

Armor developments

Improvements to the armor of main battle tank
Main battle tank
A main battle tank , also known as a battle tank or universal tank, is a tank that fills the heavy direct fire role of many modern armies. They were originally conceived to replace the light, medium, heavy and super-heavy tanks. Development was spurred onwards in the Cold War with the development...

s have reduced the usefulness of HEAT warheads by making man portable HEAT missiles heavier, although many of the world's armies continue to carry man portable HEAT rocket launchers for use against vehicles and bunkers. In unusual cases, shoulder-launched HEAT rockets are believed to have shot down U.S. helicopters in Iraq. Today HEAT rounds are primarily used in shoulder-launched and in jeep
Jeep is an automobile marque of Chrysler . The first Willys Jeeps were produced in 1941 with the first civilian models in 1945, making it the oldest off-road vehicle and sport utility vehicle brand. It inspired a number of other light utility vehicles, such as the Land Rover which is the second...

- and helicopter
A helicopter is a type of rotorcraft in which lift and thrust are supplied by one or more engine-driven rotors. This allows the helicopter to take off and land vertically, to hover, and to fly forwards, backwards, and laterally...

-based missile systems. Tanks mostly use the more effective APFSDS rounds.

The reason for the ineffectiveness of HEAT munitions against modern main battle tanks can be attributed in part to the use of new types of armor. The jet created by the explosion of the HEAT round must have a certain distance from the target and must not be deflected. Reactive armor attempts to defeat this with an outward directed explosion under the impact point, causing the jet to deform and so greatly reducing penetration power. Alternatively, composite armor featuring ceramic
A ceramic is an inorganic, nonmetallic solid prepared by the action of heat and subsequent cooling. Ceramic materials may have a crystalline or partly crystalline structure, or may be amorphous...

s erode the liner jet more quickly than rolled homogeneous armor steel, the then-preferred material in the construction of armored fighting vehicles.

Spaced armor and slat armor are also designed to defend against HEAT rounds, protecting the vehicle by causing a premature detonation of the explosive at a relatively safe distance away from the main armor of the vehicle.


Many HEAT-armed missiles today have two (or more) separate warheads (known as a tandem charge) to be more effective against reactive or multilayered armor; the first, smaller warhead initiates the reactive armor, while the second (or other), larger warhead penetrates the armor below. This approach requires highly sophisticated fuzing electronics to set off the two warheads the correct time apart, and also special barriers between the warheads to stop unwanted interactions; this makes them rather more expensive to produce.

Some anti-armor weapons incorporate a variant on the shaped charge concept that, depending on the source, can be called a Explosively Formed Penetrator
Explosively Formed Penetrator
An explosively formed penetrator , also known as an explosively formed projectile, a self-forging warhead, or a self-forging fragment, is a special type of shaped charge designed to penetrate armour effectively at standoff distances...

 (EFP), Self Forging Fragment (SFF), SElf FOrging Projectile (SEFOP), plate charge, or Misznay Schardin
Misznay-Schardin effect
The Misznay–Schardin effect, or platter effect, is a characteristic of the detonation of a broad sheet of explosive. The explosive blast expands directly away from the surface of an explosive...

 (MS) charge. This warhead type uses the interaction of the detonation wave(s), and to a lesser extent the propulsive effect of the detonation products, to deform a dish/plate of metal (iron, tantalum, etc.) into a slug-shaped projectile of low length to diameter ratio (L to D) and project this towards the target at around two kilometres per second.

The SFF is relatively unaffected by first generation reactive armor, it can also travel up to, and above 1000 cone diameters (CDs) before its velocity becomes ineffective at penetrating armor due to aerodynamic drag, or hitting the target becomes a problem. The impact of a SFF normally causes a large diameter, but relatively shallow hole (in comparison to a shaped charge) of, at best, a few CDs. If the SFF perforates the armor, extensive behind armor damage (BAD, also called behind armor effect (BAE)) occurs. The BAD is mainly caused by the high temperature and velocity armor and slug fragments being injected into the interior space and also overpressure (blast) caused by the impact.

More modern SFF warhead versions, through the use of advanced initiation modes, can also produce rods (stretched slugs), multi-slugs and finned projectiles, and this in addition to the standard short L to D ratio projectile. The stretched slugs are able to penetrate a much greater depth of armor, at some loss to BAD, multi-slugs are better at defeating light and/or area targets and the finned projectiles have greatly enhanced accuracy. The use of this warhead type is mainly restricted to lightly armored areas of MBTs—the top, belly and rear armored areas for example. It is well suited for use in the attack of other less heavily armored armored fighting vehicles (AFVs) and in the breaching of material targets (buildings, bunkers, bridge supports, etc.). The newer rod projectiles may be effective against the more heavily armored areas of MBTs.

Weapons using the SEFOP principle have already been used in combat; the smart submunitions in the CBU-97 cluster bomb used by the US Air Force and US Navy in the 2003 Iraq war used this principle, and the US Army is reportedly experimenting with precision-guided artillery shells under Project SADARM (Seek And Destroy ARMor). There are also various other projectile (BONUS, DM 642) and rocket submunitions (Motiv-3M, DM 642) and mines (MIFF, TMRP-6) that use SFF principle.

With the effectiveness of gun-fired single charge HEAT rounds being lessened, or even negated by the increasingly sophisticated armoring techniques, a class of HEAT rounds known as high-explosive anti-tank multi-purpose, or HEAT-MP, has become more popular. These are essentially HEAT rounds which are effective against older tanks and other armored vehicles, but have improved fragmentation, blast and fuzing. This gives the projectiles an overall reasonable light armor and anti-personnel/materiel effect so that they can be used in place of conventional high-explosive rounds against infantry and other battlefield targets. This reduces the total number of rounds that need to be carried for different roles, which is particularly important for modern tanks like the M1 Abrams
M1 Abrams
The M1 Abrams is a third-generation main battle tank produced in the United States. It is named after General Creighton Abrams, former Army Chief of Staff and Commander of US military forces in Vietnam from 1968 to 1972. The M1 is a well armed, heavily armored, and highly mobile tank designed for...

, due to the sheer size of 120 mm rounds used. The M1A1/M1A2 tank can carry only 40 rounds for its 120 mm M256 gun—the M60A3 Patton
M60 Patton
The 105 mm Gun Full Tracked Combat Tank, M60, also known unofficially as the M60 Patton, is a first-generation main battle tank introduced in December 1960. It was widely used by the U.S. and its Cold War allies, especially those in NATO, and remains in service throughout the world today...

tank (the Abrams' predecessor), carried 63 rounds for its 105 mm M68 gun. This effect is reduced by the higher first round hit rate of the Abrams with its improved fire control system compared to the M60. The frequent fuel replenishments required for the Abrams' fuel-hungry turbine also make simultaneous ordnance replenishment a marginal burden.

High explosive dual purpose

Another variation on HEAT warheads is surrounding them with a conventional fragmentation casing, to allow the warhead to be more effectively used for blast and fragmentation attacks on unarmored targets. In some cases this is merely a side effect of the armor-piercing design, in other cases a dual role is specifically designed in. Some warheads have been known as HEDP—High Explosive Dual Purpose.
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