Bullet

A bullet is an ammunition that only uses the kinetic energy (KE) of its projectile to penetrate the target surface such as armor . That is why there are no explosives or detonators in the projectile itself .

Other common names for balancing projectiles are tank grenades (PzGr), KE projectiles and, due to the projectile shape, arrow balancing projectiles . The term KE-Penetrator is also used for the projectile, due to the mode of action and based on the common English term (from the Latin penetrare = to penetrate).

Definition of terms and usage

Even if the term bullet applies in principle to many other projectiles such as pistol or rifle bullets or even crossbow bolts and air rifle pellets, it is used almost exclusively for armor-piercing projectiles for military applications .

Military bullets are used by all armies around the world to destroy medium to heavily armored targets. They are primarily used to fight battle tanks , armored personnel carriers or bunkers . Due to the change in warfare, away from direct fire fighting between battle tanks and towards asymmetrical warfare , they have lost some of their central and prominent role in military equipment today.

Structure and effect

material

The actual projectile consists of a metal , an optionally hardened alloy or a ceramic, each of the highest possible density . Due to the high density and hardness, most of the kinetic energy (force) is used to penetrate the armor. Today sintered tungsten carbide or depleted uranium (DU = depleted uranium) is usually used for balancing projectiles , whereby the latter are often referred to as uranium ammunition .

Working principle

Due to its high kinetic energy and the mostly relatively thin and sharpened arrow shape, the projectile displaces the material when it hits and penetrates, which due to its inertia can no longer react with elastic and plastic deformation in order to absorb the energy. The principle of action and penetration is comparable to that of a pneumatic nailer , which concentrates large kinetic energy on the very small nail tip.

When penetrating the armor, the kinetic energy is partly converted into pressure and thus also high temperature. When penetrating the armor, the strong friction between the penetrator and the armor plates creates a "rain of splinters" of burning material, which shoots inwards with the penetrator at very high speed.

The effect in the target is based on the splintering of the armor and the projectile on the back of the penetrated target area as well as the shooting in of the molten material and pyrophoric particles of armor and penetrator, which have an almost explosive effect. The crew is wounded or killed, the target is badly damaged inside by the fragmentation effect and fire and often also destroyed by secondary damage such as the ignition of fuel or the explosion of the ammunition present in the target .

When designed as sub-caliber ammunition , the actual projectile - the so-called “penetrator” - has the shape of an arrow and is guided in the gun barrel with a sabot. The sabot, which today is usually made of plastic or CFRP , is used to adjust the caliber and to seal the cannon and falls off as soon as it leaves the muzzle due to the high air resistance . Such ammunition is usually called sabot or sabot ammunition or has the abbreviation DS ( Discarding Sabot ) in its abbreviation.

Even modern composite armor , such as Chobham armor , Mexas , or reactive armor, offer only limited protection compared to the latest mass bullets from large-caliber armored cannons, especially when they are less than about a kilometer away.

Emergence

The first bullets made of tungsten had already been used by the German Wehrmacht since the beginning of the Second World War (designation: "Panzergranate ROT" or Panzergranate 40 ). Early types of ammunition designed as balancing bullets were still full-caliber bullets. The tubes had a twist with trains and fields, which set the projectiles in longitudinal rotation for stabilization. Today's massive bullets of larger caliber, which are normally fired from smoothbore cannons in main battle tanks , are under-caliber and are provided with fins or tail units for stabilization.

Types of armor-piercing bullets

Since there are hardly any unambiguous names for the different types of projectile in the German language, the following overview is structured according to the common English abbreviations:

AP

The designation AP stands for Armor Piercing (armor piercing) and represents the first generation of armor piercing projectiles. AP also basically stands for armor piercing ammunition. The projectiles consisted of a material with a very high density such as tungsten and penetrated the armor due to the kinetic energy that they gave off when they hit the target. However, AP projectiles had limits in their effectiveness, as the poor aerodynamic shape increased the air resistance and thus reduced the speed at the target. The problem with AP ammunition is the initial shock that acts on the hard and therefore mostly brittle projectile. This often resulted in the projectile splitting on the outside of the armor. To solve this problem, the APC was developed.

API

The abbreviation API (also written AP-I) stands for Armor Piercing, Incendiary . An inflammable substance ( e.g. zirconium ) is added to the AP bullet in order to create an additional fire effect after penetrating the armor. This is intended to increase the probability of destruction in the event of a hit by ignited fuel, a cook off of the stored ammunition or by other effects of fire and smoke. This type is particularly used by small to medium-caliber weapons against lightly armored targets.

APC

APC stands for Armor Piercing, Capped (armor piercing, with a cap). In the case of the APC, the tip of the hard bullet was provided with a cap made of softer material, which absorbs the impact shock and protects the actual body. It then only hits the armor after the cap has been deformed in order to penetrate it. Although this cap improved the penetration behavior of the projectile, it had aerodynamic disadvantages due to the optimization of the shape for the absorption of the impact shock, which made the projectile unstable during flight.

APBC

The fact of the unfavorable aerodynamics of the AP was first countered by using a further covering, the ballistic hood . It was made of soft metal and was used purely to optimize ballistics. This hood deformed or disintegrated when it hit a target and the projectile then followed the AP principle. APBC means Armor Piercing Ballistic Cap (armor piercing, with a ballistic hood).

APCBC

After neither the APC nor the APBC had proven to be ideal, their structure was combined in a new type of ammunition. This is how the APCBC ( Armor Piercing Capped Ballistic Cap , armor piercing, with cap and ballistic hood) was born.

The German tank shell 39, which was widely used in World War II, was an example of an APCBC. However, it is a hybrid form of the APCBC, as a projectile was provided with a small charge of explosives, which should detonate the projectile after penetrating the surface, and was also provided with a pyrotechnic charge (tracer). According to today's nomenclature, the classification would be APCBC-HE-T (Armor Piercing Capped Ballistic Cap-High Explosive-Tracer).

APCR

→ Main article : hard core bullet

APCR (Armor Piercing, Composite Rigid) , also HVAP (High Velocity Armor Piercing) , hard core ammunition or hard core projectile , were developed in 1940 for the 37 mm cannon of the German Panzerkampfwagen III and were also used by the US Army towards the middle of World War II in order to counter the new German tank types such as Panzer V Panther and Panzer VI Tiger , whose strong armor could no longer be penetrated with conventional AP or APC projectiles previously used. APCR bullets had a further, even harder core inside the bullet, which was smaller than the caliber used and could also penetrate the armor of the new German tanks.

This type of ammunition is also used in long weapons , such as military assault rifles and sniper rifles , when material-damaging effects are required, for example to shut down the engines of vehicles, or when opponents are to be fought with body armor .

APCNR

APCNR (Armor Piercing, Composite Non-Rigid) are very similar in structure to the APCR, only they are fired from butted (caliber decreasing towards the muzzle) gun barrels. The two possibilities for the butting were on the one hand to butt the pipe itself, on the other hand only to achieve a taper at the mouth through a kind of attachment. The full-caliber bullet then leaves the muzzle with a smaller diameter than originally, i.e. it is under-caliber and, by constricting the bullet, achieves a very stable trajectory and bullet speed. However, the APCNR could not prevail due to its complexity and high wear and tear. The successor to the APCNR was the APDS ammunition.

APDS

APDS ammunition (Armor Piercing, Discarding Sabot) is twist-stabilized and is used, among other things, in older drawbar cannons (for example the L7 ) or in medium-caliber weapons such as heavy machine guns and machine cannons. It is an AP bullet with a sabot. Due to the sub-caliber projectile, the flight path is more stable and the speed is higher. One example is the "20 mm APDS-DU" (APDS - Depleted Uranium). The ammunition was developed shortly before the Second World War in France by the Brandt company.

FAPDS

→ Main article : FAPDS

The frangible armor piercing discarding sabot ammunition is a further development of the APDS. During the penetration of the armor layers, it disintegrates into ever more and ever smaller parts. This has an effect similar to that of a shot load fired inside the armor: simply shooting through the target object is avoided and cascading destruction increases losses and damage.

APFSDS

Since spin-stabilized projectiles are limited in terms of muzzle velocity and length and thus also in terms of penetration power, the armor-piercing, wing -stabilized sabot projectiles (APFSDS for Armor Piercing Fin-Stabilized Discarding Sabot ) were developed. They represent the latest stage of development of large-caliber balancing projectiles introduced in the military. The projectiles commonly used today are usually fired from smooth cannon barrels and consist of a light jacket - the sabot  - and a thin, pointed, heavy metal arrow - the penetrator. It is stabilized with fins or fins. The diameter of the penetrator is significantly smaller than the caliber of the cannon, which means that it is a sub-caliber bullet. The energy of the bullet is concentrated in the thin metal arrow and the penetration power is increased.

Today, this type of ammunition is normally designed as caseless ammunition in battle tanks with a propellant charge mainly made of nitrocellulose .

The muzzle velocity of modern APFSDS projectiles is between 1400 and 1800 meters per second (m / s), that is sometimes more than five times the speed of sound . An example of such a projectile is the DM 53 , which is used today in the Leopard 2 by the German army . In combination with the 120 mm smooth barrel cannon L / 55 from Rheinmetall, it achieves a muzzle velocity of up to 1750 m / s. According to the Bundeswehr, a penetration capacity of 810 mm armor steel (according to RHA ) can be achieved over a distance of 2000 m. The precise information about the penetration capacity and muzzle velocity are, however, strictly confidential for the majority of these modern projectiles.

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  Launch phases of an APFSDS

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  APFSDS (-T) of French origin

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  APFSDS, the sabot comes off shortly after leaving the pipe, at the end of the ignited flare

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  Soviet BM 15 (caliber 125 mm)

Overview of projectile energy and penetration performance

Illustration of the kinetic energy

A locomotive with a mass of 50 tons and a speed of 80 km / h (22.2 m / s) has a kinetic energy of around 12.3 mega joules (MJ).

The armor-piercing ammunition DM 63 with a core made of tungsten carbide, which was launched in the Bundeswehr in 2005 and fired from a 120 mm smooth-barreled L / 55 cannon , achieves a muzzle velocity of 1750 m / s and a penetrator mass that is higher than that of the previous version (approx. 5 kg) about 13 MJ at the mouth.

APFSDS penetration performance

Penetrating power of different types of ammunition APFSDS

Ammunition type	Year of development	Developing country	Penetrator	Penetration (mm RHA )	Angle (in °)	Distance (in m)
115 mm 3BM-3	1961	Soviet Union	steel	115 mm	60	1000
105 mm L64A4	1978	United Kingdom	Tungsten carbide	250	0	1000
105 mm M111	Late seventies	Israel	Tungsten carbide	360	0	2000
105 mm M774	1979	United States	depleted uranium	385	0	2000
120 mm DM 13	1979	Germany	Tungsten carbide	230	0	2200
120 mm M827	1979	United States	Tungsten carbide	520	0	1000
105 mm OLF105F1	1981	France	Tungsten carbide	420	0	2000
105 mm M833	1983	United States	Tungsten carbide	480	0	1000
120 mm DM 23	1985	Germany	Tungsten carbide	480	0	1000
120 mm M829	1985	United States	depleted uranium	540	0	1000
125 mm 3BM32 "Want"	1987	Soviet Union	depleted uranium	500	0	1000
105 mm OLF105E2	1988	France	depleted uranium	540	0	2000
120 mm DM 23A1	1988	Germany	Tungsten carbide	540	0	1000
125 mm 3BM42 "Mango"	1988	Soviet Union	Tungsten carbide	440	0	1000
120 mm M829A1	1989	United States	depleted uranium	700	0	1000
125 mm 3BM48 "Swinez"	1991	Soviet Union	depleted uranium	600	0	1000
120 mm M829A2	1992	United States	depleted uranium	740	0	1000
120 mm CHARM1	1994	United Kingdom	depleted uranium	540	0	1000
120 mm OLF120G1	Early nineties	France	Tungsten carbide	540	0	1000
120 mm DM 43	1995	Germany	Tungsten carbide	640	0	1000
120 mm CHARM3	1999	United Kingdom	depleted uranium	740	0	1000
120 mm DM 53	2000	Germany	Tungsten carbide	600-640	0	1000
125 mm 3BM59 "Swinez" -1	2002	Russia	depleted uranium	740	0	1000
125 mm 3BM60 "Swinez" -2	2002	Russia	Tungsten carbide	640-660	0	1000
120 mm DM 63	2004?	Germany	Tungsten carbide	750	0	1000
120 mm M829A3	2003	United States	depleted uranium	800	0	1000
125 mm 3BM69 "Wakiim" -1	2005	Russia	depleted uranium	900	0	1000
125 mm 3BM70 "Wakiim" -2	2005	Russia	Tungsten carbide	800	0	1000

Suitable accelerators

In use, balancing projectiles are accelerated by conventional propellant charges in cannons . In principle, railguns and two-stage light gas cannons would also be suitable for firing mass bullets. An even higher speed and thus kinetic energy could be achieved with this. Such accelerators have only been used in research so far; there are no operational weapons systems.

Protective measures

So far there have been no effective protective measures against modern large-caliber high-performance balancing projectiles. Even the most modern armor was still penetrated at combat distances of several kilometers. Whether this principle is still valid due to the further development of the Russian battle tanks T-80 , T-90 and T-14 is open due to the secrecy.

With the development of new armor-piercing ammunition and accelerator concepts on the one hand and modern armor concepts in connection with distance-active protective measures  - in particular the so-called "hardkill systems" - on the other hand, the "competition" is intensifying again. Practical experience has not yet shown whether the hardkill systems in particular will be able to impair the effectiveness of such projectiles, prevent the hit or destroy the approaching penetrator.

See also

• Rheinmetall new tank cannon 140
• Steyr IWS 2000

literature

• Beat Kneubuehl: Projectiles (Volume 1) - Ballistics, accuracy, effectiveness. Motorbuch Verlag, 1998, ISBN 978-3-7276-7119-7 .
• Beat Kneubuehl: Projectiles (Volume 2) - ballistics, effectiveness, measurement technology. Motorbuch Verlag, 2004, ISBN 978-3-7276-7145-6 .

Web links

• Rheinmetall Detec for DM 53.
• Canadian Museum “Juno Beach Center” on ammunition from World War II.

Individual evidence

1. ↑ ^{a b} Richard Ogorkiewicz : Tanks 100 years of evolution . Bloomsbury Publishing, 2015, ISBN 1-4728-1305-7 , pp. 255 ( limited preview in Google Book search).
2. ↑ Data sheet 02/2006 - Leopard 2 . www.y-punkt.de. Archived from the original on June 7, 2014. Retrieved September 14, 2013.
3. ↑ Paul-Werner Krapke: Leopard 2 his becoming and his performance. Page 9 of the supplement by Rolf Hilmes , Books on Demand GmbH, Norderstedt 2004, ISBN 3-8334-1425-1
4. ↑ Tankograd: T-62. thesovietarmourblog.blogspot.com, accessed October 7, 2018 . 
5. ↑ ^{a b c d e f} 105 mm ammo. echo501.tripod.com, accessed November 13, 2018 . 
6. ↑ Ammunition from Rheinmetall's 120 mm cannon. www.kotsch88.de, accessed on November 13, 2018 . 
7. ↑ Why politics refused the Leo uranium bullets. April 26, 2015, accessed July 24, 2018 .