Armor-piercing shot and shell - AbsoluteAstronomy.com

An armor-piercing shell is a type of ammunition

Ammunition

Ammunition is a generic term derived from the French language la munition which embraced all material used for war , but which in time came to refer specifically to gunpowder and artillery. The collective term for all types of ammunition is munitions...

designed to penetrate armor. From the 1860s to 1950s, a major application of armor-piercing projectiles was to defeat the thick armor carried on many warships. From the 1920s onwards, armor-piercing weapons were required for anti-tank missions. Furthermore it is used to defeat concrete

Concrete

Concrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...

, ballistic vests, bulletproof glass

Bulletproof glass

Bulletproof glass is a type of strong but optically transparent material that is particularly resistant to being penetrated when struck by bullets, but is not completely impenetrable. It is usually made from a combination of two or more types of glass, one hard and one soft...

, and other defenses.

An armor-piercing shell

Shell (projectile)

A shell is a payload-carrying projectile, which, as opposed to shot, contains an explosive or other filling, though modern usage sometimes includes large solid projectiles properly termed shot . Solid shot may contain a pyrotechnic compound if a tracer or spotting charge is used...

must withstand the shock of punching through armor plating. Shells designed for this purpose have a greatly strengthened case with a specially hardened and shaped nose, and a much smaller bursting charge. Some smaller-caliber

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....

AP shells have an inert filling, or incendiary charge in place of the HE bursting charge. The AP shell is now little used in naval warfare, as modern warships have little or no armor protection, but it remains the preferred round in tank warfare, as it has a greater "first-hit kill" probability than a high explosive anti-tank

Heat

In physics and thermodynamics, heat is energy transferred from one body, region, or thermodynamic system to another due to thermal contact or thermal radiation when the systems are at different temperatures. It is often described as one of the fundamental processes of energy transfer between...

(HEAT) round, especially against a target with composite armor, and because of higher muzzle velocity

Muzzle velocity

Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...

, is also more accurate than a HEAT round.

Armor-piercing cartridges

Cartridge (firearms)

A cartridge, also called a round, packages the bullet, gunpowder and primer into a single metallic case precisely made to fit the firing chamber of a firearm. The primer is a small charge of impact-sensitive chemical that may be located at the center of the case head or at its rim . Electrically...

are also available as small arms ammunition, primarily for use as an anti-matériel

Anti-materiel rifle

An anti-materiel rifle is a rifle that is designed for use against military equipment rather than against other combatants ....

round or to defeat body armor.

History

The late 1850s saw the development of the ironclad warship

Ironclad warship

An ironclad was a steam-propelled warship in the early part of the second half of the 19th century, protected by iron or steel armor plates. The ironclad was developed as a result of the vulnerability of wooden warships to explosive or incendiary shells. The first ironclad battleship, La Gloire,...

, which carried wrought iron

Wrought iron

thumb|The [[Eiffel tower]] is constructed from [[puddle iron]], a form of wrought ironWrought iron is an iron alloy with a very low carbon...

armor of considerable thickness. This armor was practically immune to both the round cast-iron cannonballs then in use and to the recently developed explosive shell. The first solution to this problem was effected by Major Sir W. Palliser

William Palliser

Major Sir William Palliser CB MP was an Irish-born politician and inventor, Member of Parliament for Taunton from 1880 until his death.-Early life:...

, who invented a method of hardening the head of the pointed cast-iron shot. By casting the projectile point downwards and forming the head in an iron mold, the hot metal was suddenly chilled and became intensely hard (resistant to deformation), while the remainder of the mold, being formed of sand, allowed the metal to cool slowly and the body of the shot to be made tough
Toughness
In materials science and metallurgy, toughness is the ability of a material to absorb energy and plastically deform without fracturing; Material toughness is defined as the amount of energy per volume that a material can absorb before rupturing...

(resistant to shattering).

These chilled iron shots proved very effective against wrought iron armor, but were not serviceable against compound and steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

armor, which was first introduced in the 1880s. A new departure therefore had to be made, and forged steel

Forging

Forging is a manufacturing process involving the shaping of metal using localized compressive forces. Forging is often classified according to the temperature at which it is performed: '"cold," "warm," or "hot" forging. Forged parts can range in weight from less than a kilogram to 580 metric tons...

rounds with points hardened

Hardening (metallurgy)

Hardening is a metallurgical and metalworking process used to increase the hardness of a metal. The hardness of a metal is directly proportional to the uniaxial yield stress at the location of the imposed strain...

by water took the place of the Palliser shot

Palliser shot

Palliser shot was invented by Sir William Palliser and hence its name. It was an early British armour-piercing artillery projectile, intended to pierce the armour protection of warships being developed in the second half of the 19th century.-History:...

. At first, these forged-steel rounds were made of ordinary carbon steel, but as armor improved in quality, the projectiles followed suit.

During the 1890s and subsequently, cemented

Cementation process

The cementation process is an obsolete technique for making steel by carburization of iron. Unlike modern steelmaking, it increased the amount of carbon in the iron. It was apparently developed before the 17th century. Derwentcote Steel Furnace, built in 1720, is the earliest surviving example...

steel armor became commonplace, initially only on the thicker armor of warships. To combat this, the projectile was formed of steel—forged or cast—containing both nickel

Nickel

Nickel is a chemical element with the chemical symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile...

and chromium

Chromium

Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...

. Another change was the introduction of a soft metal cap over the point of the shell.

First World War era

Shot and shell used prior to and during World War I

World War I

World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...

were generally cast from special chromium

Chromium

(stainless) steel that was melted in pots. They were forged into shape afterward and then thoroughly annealed

Annealing (metallurgy)

Annealing, in metallurgy and materials science, is a heat treatment wherein a material is altered, causing changes in its properties such as strength and hardness. It is a process that produces conditions by heating to above the recrystallization temperature, maintaining a suitable temperature, and...

, the core bored at the rear and the exterior turned up in a lathe

Lathe (metal)

A metal lathe or metalworking lathe is a large class of lathes designed for precisely machining relatively hard materials. They were originally designed to machine metals; however, with the advent of plastics and other materials, and with their inherent versatility, they are used in a wide range of...

. The projectiles were finished in a similar manner to others described above. The final, or tempering

Tempering

Tempering is a heat treatment technique for metals, alloys and glass. In steels, tempering is done to "toughen" the metal by transforming brittle martensite or bainite into a combination of ferrite and cementite or sometimes Tempered martensite...

treatment, which gave the required hardness/toughness profile (differential hardening) to the projectile body, was a closely guarded secret.

The rear cavity of these projectiles was capable of receiving a small bursting charge of about 2% of the weight of the complete projectile; when this is used, the projectile is called a shell, not a shot. The HE filling of the shell, whether fuze

Fuze

Fuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize...

d or unfuzed, had a tendency to explode on striking armor in excess of its ability to perforate.

Second World War

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...

, projectiles used highly alloyed steels containing nickel

Nickel

-chromium-molybdenum

Molybdenum

Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...

, although in Germany, this had to be changed to a silicon

Silicon

Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...

-manganese

Manganese

Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...

-chromium-based alloy when those grades became scarce. The latter alloy, although able to be hardened to the same level, was more brittle and had a tendency to shatter on striking highly sloped armor. The shattered shot lowered penetration, or resulted in total penetration failure; for armor-piercing high-explosive (APHE) projectiles, this could result in premature detonation of the HE filling. Highly advanced and precise methods of differentially hardening the projectile were developed during this period, especially by the German armament industry. The resulting projectiles gradually change from high hardness (low toughness) at the head to high toughness (low hardness) at the rear and were much less likely to fail on impact.

APHE shells for tank guns, although used by most forces of this period, were not used by the British. The only British APHE projectile was the Shell AP, Mk1 for the 2 pdr anti-tank gun

Ordnance QF 2 pounder

The Ordnance QF 2-pounder was a British anti-tank and vehicle-mounted gun, employed in the Second World War. It was actively used in the Battle of France, and during the North Africa campaign...

and this was dropped as it was found that the fuze

Fuze

tended to separate from the body during penetration. Even when the fuze didn’t separate and the system functioned correctly, damage to the interior was little different from the solid shot, and so did not warrant the additional time and cost of producing a shell version. APHE projectiles of this period used a bursting charge of about 1–3% of the weight of the complete projectile, the filling detonated by a rear mounted delay fuze

Fuze

. The explosive used in APHE projectiles needs to be highly insensitive to shock to prevent premature detonation. The US forces normally used the explosive Explosive D

Dunnite

Dunnite, also known as Explosive D or systematically as ammonium picrate, is an explosive developed by Major Dunn in 1906. Ammonium picrate is a salt formed by reacting picric acid and ammonia....

, otherwise known as ammonium picrate, for this purpose. Other combatant forces of the period used various explosives, suitability desensitized (usually by the use of waxes mixed with the explosive).

Due to the increase in armor thickness during the conflict, the projectiles’ impact velocity had to be increased to ensure perforation. At these higher velocities, the hardened tip of the shot or shell has to be protected from the initial impact shock, or risk shattering. To raise the impact velocity and stop the shattering, they were initially fitted with soft steel penetrating caps. The best performance penetrating caps were not very aerodynamic, so an additional ballistic cap was later fitted to reduce drag. The resulting projectile types were named armor-piercing capped (APC) and armor-piercing capped ballistic capped (APCBC

APCBC

The armour-piercing capped ballistic cap is a type of armor-piercing shell introduced in the 1930s.-Development:The APCBC munition type was an evolutionary development of the early war armour-piercing capped shell, itself an evolution of the more basic AP and APHE shell types...

).

Early WWII-era uncapped AP projectiles fired from high-velocity guns were able to penetrate about twice their caliber at close range (100 m). At longer ranges (500-1,000 m), this dropped 1.5–1.1 calibers due to the poor ballistic shape and higher drag of the smaller-diameter early projectiles. Later in the conflict, APCBC fired at close range (100 m) from large-caliber, high-velocity guns (75–128 mm) were able to penetrate a much greater thickness of armor in relation to their caliber (2.5 times) and also a greater thickness (2–1.75 times) at longer ranges (1,500–2,000 m).

Armor-piercing shot

Armor-piercing "shot" for cannons tend to combine some form of incendiary capability with that of armor-penetration. The incendiary compound is normally contained between the cap and penetrating nose, within a hollow at the rear, or a combination of both. If the projectile also uses a tracer

Tracer ammunition

Tracer ammunition are bullets that are built with a small pyrotechnic charge in their base. Ignited by the burning powder, the phosphorus tail burns very brightly, making the projectile visible to the naked eye...

, the rear cavity is often used to house the tracer compound. For larger-caliber projectiles, the tracer may instead be contained within an extension of the rear sealing plug. Common abbreviations for solid (non-composite/hardcore) cannon-fired shot are; AP, AP-T, API and API-T; where "T" stands for "tracer" and "I" for "incendiary"

Armor-piercing shells

Armor-piercing shells in the classic form are not common in modern guns, though they may be found in the larger (40–57 mm) weapons, especially those of Russian- or Soviet-era descent. Modern guns instead fire semi-armor-piercing high-explosive (SAPHE) shells, which have less anti-armor capability, but far greater anti-materiel/personnel effects. The modern SAPHE projectiles still have a ballistic cap, hardened body and base fuze, but tend to have a far thinner body material and higher explosive content (4–15%). Common abbreviations for modern AP and SAP shells are: HEI(BF), SAPHE, SAPHEI, and SAPHEI-T.

Most modern active protection systems (APS) are unlikely to be able to defeat full-caliber AP rounds fired from a large-caliber tank gun, due to the high mass of the shot, its rigidity, short overall length, and thick body. The APS uses fragmentation warheads or projected plates, and both are designed to defeat the two most common anti-armor projectiles in use today: HEAT

Heat

and kinetic energy penetrator

Kinetic energy penetrator

A kinetic energy penetrator is a type of ammunition which, like a bullet, does not contain explosives and uses kinetic energy to penetrate the target....

. The defeat of HEAT projectiles is accomplished through damage/detonation of the HEAT's explosive filling or damage to the shaped charge liner or fuzing system, and defeat of kinetic energy projectiles is accomplished by inducing yaw/pitch or fracturing of the rod.

Small arms

Armor-piercing rifle and pistol cartridges

Cartridge (firearms)

are usually built around a penetrator of hardened steel

Hardened steel

The term hardened steel is often used for a medium or high carbon steel that has been given the heat treatments of quenching followed by tempering. The quenching results in the formation of metastable martensite, the fraction of which is reduced to the desired amount during tempering. This is the...

or tungsten

Tungsten

Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...

. Aircraft and tank rounds sometimes use a core of depleted uranium

Depleted uranium

Depleted uranium is uranium with a lower content of the fissile isotope U-235 than natural uranium . Uses of DU take advantage of its very high density of 19.1 g/cm3...

. The penetrator is a pointed mass of high-density material that is designed to retain its shape and carry the maximum possible amount of energy as deeply as possible into the target. Depleted-uranium penetrators have the advantage of being pyrophoric

Pyrophoricity

A pyrophoric substance is a substance that will ignite spontaneously in air. Examples are iron sulfide and many reactive metals including uranium, when powdered or sliced thin. Pyrophoric materials are often water-reactive as well and will ignite when they contact water or humid air...

and self-sharpening on impact, resulting in intense heat and energy focused on a minimal area of the target's armor. Some rounds also use explosive

Explosive material

An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...

or incendiary

Incendiary device

Incendiary weapons, incendiary devices or incendiary bombs are bombs designed to start fires or destroy sensitive equipment using materials such as napalm, thermite, chlorine trifluoride, or white phosphorus....

tips to aid in the penetration of thicker armor. High Explosive Incendiary/Armor Piercing Ammunition

High Explosive Incendiary/Armor Piercing Ammunition

High Explosive Incendiary/Armor Piercing Ammunition is a form of shell which combines both an armor-piercing capability and a high-explosive effect. In this respect it is a modern version of armor piercing shell...

combines a tungsten carbide penetrator with an incendiary and explosive tip.

Rifle armor-piercing ammunition generally carries its hardened penetrator within a copper

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...

or cupronickel

Cupronickel

Cupronickel or copper-nickel or "cupernickel" is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. Cupronickel is highly resistant to corrosion in seawater, because its electrode potential is adjusted to be neutral with regard to seawater...

jacket, similar to the jacket which would surround lead

Lead

Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...

in a conventional projectile. Upon impact on a hard target, the copper case is destroyed, but the penetrator continues its motion and penetrates the target. Armor-piercing ammunition for pistols has also been developed and uses a design similar to the rifle ammunition.

The entire projectile is not normally made of the same material as the penetrator because the physical characteristics that make a good penetrator (i.e. extremely tough, hard metal) make the material equally harmful to the barrel of the gun firing the cartridge.

Contrary to popular belief, Teflon (polytetrafluoroethylene) coating on bullets does not help the deep penetration. The intention is to reduce the wear of the barrel caused by hardened projectiles, or to reduce the likelihood of a ricochet.

Specific AP round examples

Round	Projectile	Weight
M2	.30-06 Springfield .30-06 Springfield The .30-06 Springfield cartridge or 7.62×63mm in metric notation, was introduced to the United States Army in 1906 and standardized, and was in use until the 1960s and early 1970s. It replaced the .30-03, 6 mm Lee Navy, and .30 US Army...	163 grains
M61	7.62×51mm NATO 7.62×51mm NATO The 7.62×51mm NATO is a rifle cartridge developed in the 1950s as a standard for small arms among NATO countries...	150.5 grains
FN P80	7.62×51mm NATO 7.62×51mm NATO The 7.62×51mm NATO is a rifle cartridge developed in the 1950s as a standard for small arms among NATO countries...	150 grains
AP485	.338 Lapua Magnum	248 grains
M995	5.56×45mm NATO	52 grains
S.m.K. K bullet Also: Patrone SmK 8x57mm ISThe K bullet is a 8x57mm IS armor-piercing bullet which has a tool steel core and which was designed to be fired from a standard Mauser rifle. It was used by the German infantry against the first British tanks in World War I...	7.92×57mm Mauser	178.25 grains

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

History

First World War era

Second World War

Armor-piercing shot

Armor-piercing shells

Small arms

Specific AP round examples

See also

External links