Sub-caliber projectiles with a tungsten core. What is a sub-caliber projectile? The principle of operation of a sub-caliber projectile. Sharp-headed chamber shell
BOPS (Armor-piercing feathered sub-caliber projectiles)
With the adoption of the T-62 medium tank, the USSR became the first country in the world to massively use armor-piercing feathered sub-caliber ammunition (BOPS) in tank ammunition. Due to the extremely high speed and long range direct shot.
Armor-piercing shells for the 115-mm gun U-5TS (2A20) were superior in armor penetration at an angle of 60 degrees. from the normal, the best sub-caliber shells for rifled guns by 30% and had a direct shot range 1.6 times greater than regular ones. However, unitary shots for the GSP U-5TS did not allow to fully realize the potential for rate of fire and reduce the internal reserved volume of a promising tank, in addition, due to increased gas contamination fighting compartment T-62 designers were forced to resort to a mechanism for removing spent cartridges, which somewhat reduced the rate of fire of the tank. Thus, the problem of automating the process of loading a tank gun became urgent, which, along with an increase in the rate of fire, significantly reduced the internal volume, and, consequently, security.
At the beginning of 1961, work began on the creation of 115-mm separate-loading rounds with OBPS, cumulative and high-explosive fragmentation shells for the D-68 (2A21) gun.
Completion of work on the creation of separate loading shots for the D-68 gun, installed in a new medium tank with mechanized loading, was successfully completed, and the newly created ammunition was put into mass production in 1964.
In 1966, the T-64 tank with the D-68 gun and new shots for it was put into service.
However, for a number of reasons, the 115 mm caliber gun of the T-64 tank was considered insufficient to ensure guaranteed destruction of promising foreign tanks.
Perhaps the reason was an overestimated assessment of the armor resistance of the new, most powerful English tank of that period, the Chieftain, as well as fears of the imminent entry into service of the promising American-German MBT-70 tank, which was never put into service.
For these reasons, an improved version of the T-64 tank was created, which received the designation T-64A and was adopted by the Soviet Army in May 1968. The tank was armed with a 125 mm gun D-81T (2A26) developed in 1962 at the plant number 172 (Perm) in OKB-9 under the direction of F.F. Petrov.
Subsequently, this gun, which deserved a lot positive feedback for its high technical and operational characteristics, it underwent numerous upgrades aimed at further growth of its characteristics.
Upgraded versions of the D-81T (2A26) cannon, such as 2A46M, 2A46M-1, 2A46M-2, 2A46M-4, are the main armament of domestic tanks to this day.
BPS burning cylinder with tubular powder (SC) - Right
Burning Sleeve (SG) - Left
core - in the middle
As you can see in the pictures, a burning cylinder (SC) with tubular gunpowder is put on the BPS, the SC is made of cardboard impregnated with TNT and completely burns out during the shot and there is nothing left of it. The burning sleeve (SG) is made using a similar technology; after a shot, a metal pallet remains from it. The means of ignition is the galvano-impact sleeve GUV-7, which differs from the usual one in that it has an incandescent bridge that ignites the gunpowder when the striker is touched, but it can also work like a normal one from impact.
Domestic BPS consists of a leading ring, consisting of three sectors with a 120-degree split plane, fastened with a copper or plastic obturator band. The second support is the stabilizer feathers, equipped with bearings. When leaving the barrel, the ring is divided into three sectors and the sectors fly up to 500 m at high speed, it is not recommended to be in front of the tank firing the BPS. The sector can damage lightly armored vehicles and injure infantry.Separating sectors of the BPS have significant kinetic energy within 2 ° from the shot (at a distance of 1000 m)
A burning cylinder (SC) with tubular gunpowder is put on the OBPS, the SC is made of cardboard impregnated with TNT and completely burns out during the shot and nothing remains of it. The burning sleeve (SG) is made using a similar technology; after a shot, a metal pallet remains from it. The means of ignition is galvano-impact sleeve GUV-7.
The beginning of the 60s and the end of the seventies, the adoption of OBPS stabilized by plumage.
The period of the late 60s and late seventies was characterized by the evolutionary development of foreign tanks, the best of which had a homogeneous armor shield within 200 (Leopard-1A1), 250 (M60) and 300 (Chieftain) millimeters of armor.
Their ammunition included BPS for 105 mm L7 guns (and its American counterpart M68) and 120 mm L-11 rifled gun of the Chieftain tank.
At the same time, a number of OBPS for 115 and 125 mm GSP tanks T-62, T-64 and T-64, as well as 100 mm smoothbore anti-tank guns T-12, entered service in the USSR.
Among them were shells of two modifications: solid-shell and having a carbide core.
One-piece OBPS 3BM2 for anti-tank guns T-12, 3BM6 for GSP U-5TS of the T-62 tank, as well as one-piece OBPS for 125 mm GSP 3BM17. OBPS with a carbide core included 3BM3 for the GSP U-5TS of the T-62 tank, 125 mm OBPS 3BM15, 3BM22 for the T-64A / T-72 / T-80 tanks.
Projectile 3VBM-7 (projectile index 3BM-15; projectile index from throwing charge3BM-18 ) (p/w ca. 1972)
The active part of this projectile is slightly lengthened compared to the 3BM-12, which did not affect the overall length of the projectile due to the greater penetration of the active part into the additional charge. Despite the fact that the projectile had not been used in the Soviet Army for a long time, until the collapse of the USSR it remained the most modern OBPS available to recipients of Soviet export T-72 tanks. BM-15 and its local counterparts were produced under license in many countries.
Shot 3VBM-8 (projectile index 3BM-17; projectile index from throwing charge3BM-18) (p/w ca. 1972)
A simplified version of the 3BM-15 projectile; there is no tungsten carbide core, instead the size of the armor-piercing cap has been increased to compensate for the drop in armor penetration. Presumably used only for export and training purposes.
Shot 3VBM-9 (projectile index 3BM-22; projectile index from throwing charge3BM-23) (p / in 1976)
Research theme "Hairpin". A.h. length almost identical to a.h. BM-15, however, a much more massive armor-piercing damper is used. As a result, the projectile is noticeably heavier than the BM-15, which led to some decrease in the initial speed. This projectile was the most common in the Soviet Army in the late 70s - early 80s, and although it is no longer produced, it has been accumulated in large quantities and is still allowed for use..
Appearance core of one projectile option.
Second generation (late 70s and 80s)
In 1977, work began to improve the combat effectiveness of tank artillery rounds. The staging of these works was associated with the need to defeat new types of reinforced armor protection developed abroad for a new generation of M1 Abrams and Leopard-2 tanks.
The development of new design schemes for OBPS has begun, ensuring the destruction of monolithic combined armor in a wide range of angles of impact with the armor, as well as overcoming remote sensing.
Other tasks included improving the aerodynamic qualities of the projectile in flight in order to reduce drag, as well as increasing its muzzle velocity.
The development of new alloys based on tungsten and depleted uranium with improved physical and mechanical characteristics continued.
The results obtained from these research projects made it possible at the end of the 70s to begin the development of new OBPS with an improved master device, which ended with the adoption of the Nadezhda, Vant and Mango OBPS for the 125-mm GSP D-81.
One of the main differences between the new OBPS compared to those developed before 1977 was a new master device with sectors of the "clamp" type using aluminum alloy and polymer materials.
In OBPS, before that, leading devices with steel sectors of the "expanding" type were used.
In 1984, the OBPS 3VBM13 "Vant" was developed with the 3BM32 projectile of increased efficiency, "Vant" became the first domestic monoblock OBPS made of a uranium alloy with high physical and mechanical properties.
OBPS "Mango" was developed specifically to destroy tanks with combined and dynamic protection. The design of the projectile uses a highly efficient combined core made of tungsten alloy placed in a steel casing, between which there is a layer of low-melting alloy.
The projectile is able to overcome dynamic protection and reliably hit the complex composite armor of tanks that entered service in the late 70s and until the mid-80s.
Shot 3VBM-11 (projectile index 3BM-26; projectile index from throwing charge3BM-27) (p / in 1983)
Theme "Hope-R". This OBPS was the first in a series of projectiles with a new master device.
This ammunition was also the first to be developed and tested specifically for the purpose of fending off advanced multilayer barriers used on promising NATO tanks.
It is used with the main propellant charge 4Zh63.
3BM-29. "Nadfil-2", OBPS with a uranium core(1982) similar in design to 3BM-26.
Shot 3VBM-13 (projectile index 3BM-32; projectile index from throwing charge3BM-38 ) (p/in 1985)
Research theme "Vant". The first Soviet monolithic uranium OBPS.
Shot 3VBM-17 (projectile index 3BM-42; projectile index from throwing charge3BM-44) (p / in 1986)
The topic of research "Mango" was opened in 1983. A projectile of increased power, designed to destroy modern multilayer armored barriers. Has a very complex structure, which includes a solid ballistic and armor-piercing cap, an armor-piercing damper, and two cores made of high-strength tungsten alloy of high elongation. The cores are fixed in the body of the projectile by means of a fusible alloy jacket; in the process of penetration, the jacket melts, allowing the cores to enter the penetration channel without expending energy on separation from the body.
WU - further development of higher education used with OBPS 3BM-26 is made of V-96Ts1 alloy with improved characteristics. The projectile is widely distributed, and was also exported complete with Russian and Ukrainian tanks T-80U / T-80UD and T-90, delivered abroad in the last decade.
OBPS "Lead" (projectile index 3BM-46; projectile index from throwing charge3BM-48) (p / in 1986)
Modern OBPS with a monolithic high elongation uranium core and sub-caliber stabilizers, using a new composite VU with two contact zones. The projectile has a length close to the maximum allowable for standard Soviet automatic loaders. The most powerful Soviet 125-mm OBPS, exceeding or equal in power to the OBPS adopted by the NATO countries until relatively recently.
Shot withheightened power
A high-power projectile with a high elongation tungsten core and sub-caliber stabilizers, using a four-section composite VU with two contact zones. In the literature of Rosoboronexport, this projectile is simply referred to as a "high-powered projectile."
The developers of this munition for the first time created a projectile of large elongation with new scheme reference.
The new BPS is designed to fire from the D-81 tank gun at modern tanks equipped with complex composite armor and dynamic protection.
Compared to the BOPS 3BM42, a 20% increase in armor penetration is provided due to the elongated body made of tungsten alloy and a charge of higher-energy gunpowder.
Summary table TTX |
|||||||||
Shot Index |
3VBM-7 |
3 V BM-8 |
3VBM-9 |
3VBM-11 |
3VBM-10 |
3VBM-13 |
3VBM-17 |
3VBM-20 |
3VBM-17M |
Projectile index |
3BM-16 |
3BM-1 7 |
3BM-2 6 |
3BM-29 |
3BM-46 |
||||
Projectile index with additional charge |
3BM-18 |
3VBM- 1 8 |
3BM-3 |
3BM-27 |
3BM-30 |
3BM-38 |
3BM-44 |
3BM-48 |
3BM-44M |
Cipher |
Barrette |
Hope-R |
File-2 |
Vant |
Mango |
Lead |
Mango-M |
||
Initial speed, m/s |
1780 |
1780 |
1760 |
1720 |
1692...1700 |
1692...1700 |
1692...1700 |
1650 |
1692...1700 |
Core length, mm |
|||||||||
Weight (without VU), g |
3900 |
3900 |
3900 |
4800 |
4800 |
4850 |
4850 |
5200 |
5000 |
Core (base alloy) |
Steel |
Tungsten |
depleted uranium |
depleted Uranus |
Tungsten |
depleted Uranus |
Tungsten |
||
Scheme of reference |
Ring VU made of steel, expanding type and plumage |
WU clamping type aluminum alloy and plumage |
Two-bearing WU |
||||||
Normative penetration at 2000 m, 60° |
110…150 |
||||||||
In terms of the development of BOPS, since the late nineties, big job, the backlog of which was BOPS "Anker" and 3BM48 "Lead". These shells were significantly superior to such BOPS as Mango and Vant, the main difference was the new principles of the reference system in the bore and the core with a significantly increased elongation. New system conducting projectiles in the bore not only allowed the use of longer cores, but also made it possible to improve their aerodynamic properties.
After the collapse of the USSR, the backlog of the industry for the production of new types of ammunition began and continues. The question arose about the modernization of ammunition, both domestic tanks and those exported. The development, as well as small-scale production of domestic BPS, continued, however, the mass introduction and mass production of new generation BPS samples was not carried out.
Due to the lack of modern BPS, a number of countries with a large fleet of domestic tanks armed with a 125 mm gun have made their own attempts to develop BPS.
Comparison of OBPS caliber 125 mm 3BM48, 3BM44M, M829A2 (USA), NORINCO TK125 (PRC)
and OBPS caliber 120 mm DM53 (Germany), CL3241 (Israel).
OBPS caliber 125 mm developed in the 90s in China and Eastern Europe: NORINCO TK125, TAPNA (Slovakia), Pronit (Poland).
Immediately after the appearance of armor protection for military equipment, designers artillery weapons began work on the creation of tools capable of effectively destroying it.
An ordinary projectile was not quite suitable for this purpose, its kinetic energy was not always enough to overcome a thick barrier made of heavy-duty steel with manganese additives. The sharp tip crumpled, the body collapsed, and the effect turned out to be minimal, at best - a deep dent.
The Russian engineer-inventor S. O. Makarov developed the design of an armor-piercing projectile with a blunt front. This technical solution provided high level pressure on the metal surface at the initial moment of contact, while the place of impact was subjected to strong heating. Both the tip itself and the area of the armor that had been hit melted. The remaining part of the projectile penetrated the resulting fistula, causing destruction.
Sergeant major Nazarov did not have theoretical knowledge of metallurgy and physics, but intuitively came to a very interesting design, which became the prototype of an effective class of artillery weapons. His sub-caliber projectile differed from the usual armor-piercing one in its internal structure.
In 1912, Nazarov proposed to introduce a strong rod into ordinary ammunition, which is not inferior to armor in its hardness. Officials of the War Ministry dismissed the importunate non-commissioned officer, considering, obviously, that an illiterate retiree could not invent anything sensible. Subsequent events clearly demonstrated the harmfulness of such arrogance.
The Krupa firm received a patent for a sub-caliber projectile already in 1913, on the eve of the war. However, the level of development of armored vehicles at the beginning of the 20th century made it possible to do without special armor-piercing means. They were needed later, during the Second World War.
The principle of operation of a sub-caliber projectile is based on a simple formula known from the school physics course: a moving body is directly proportional to its mass and the square of its speed. Therefore, to ensure the greatest destructive ability, it is more important to disperse the striking object than to make it heavier.
This simple theoretical position finds its practical confirmation. A 76mm sub-caliber projectile is twice as light as a conventional armor-piercing projectile (3.02 and 6.5 kg, respectively). But to provide striking power, it is not enough just to reduce the mass. Armor, as the song says, is strong, and additional tricks are needed to break through it.
If a steel bar with a uniform internal structure hits a solid barrier, it will collapse. This process, in slow motion, looks like the initial crushing of the tip, an increase in the contact area, strong heating and spreading of molten metal around the impact site.
Armor-piercing sub-caliber projectile works differently. Its steel body shatters upon impact, taking on some of the thermal energy and protecting the heavy-duty interior from thermal destruction. The ceramic-metal core, having the shape of a somewhat elongated thread spool and a diameter three times smaller than the caliber, continues to move, punching a small-diameter hole in the armor. In this case, a large amount of heat is released, which creates a thermal distortion, which, in combination with mechanical pressure, produces a destructive effect.
The hole, which forms a sub-caliber projectile, has the shape of a funnel, expanding in the direction of its movement. It does not require damaging elements, explosives and a fuse, fragments of armor and core flying inside the combat vehicle pose a mortal threat to the crew, and the released one can cause detonation of fuel and ammunition.
Despite the diversity of anti-tank weapons, sabots, invented over a century ago, still have their place in the arsenal of modern armies.
What affects tanks besides grenade launchers and anti-tank systems? How does armor-piercing ammunition work? In this article, we will talk about armor-piercing ammunition. The article, which will be of interest to both dummies and those who understand the topic, was prepared by a member of our team, Eldar Akhundov, who pleases us once again interesting reviews on the subject of armaments.
History
Armor-piercing shells are designed to hit targets protected by armor, as their name implies. They first began to be widely used in naval battles in the second half of the 19th century with the advent of ships protected by metal armor. The action of simple high-explosive fragmentation projectiles on armored targets was not enough due to the fact that during the explosion of the projectile, the energy of the explosion is not concentrated in any one direction, but is dissipated into the surrounding space. Only part shock wave affects the armor of the object trying to break through / bend it. As a result, the pressure created by the shock wave is not enough to penetrate thick armor, but some deflection is possible. With the thickening of the armor and the strengthening of the design of armored vehicles, it was necessary to increase the amount of explosives in the projectile by increasing its size (caliber, etc.) or developing new substances, which would be costly and inconvenient. By the way, this applies not only to ships, but also to land armored vehicles.
Initially, the first tanks during the First World War could be fought with high-explosive fragmentation shells, since the tanks had bulletproof thin armor only 10-20 mm thick, which was also connected with rivets, since at that time (early 20th century) welding technology solid armored hulls of tanks and armored vehicles has not yet been worked out. It was enough 3 - 4 kg of explosives with a direct hit to put such a tank out of action. IN this case the shock wave simply tore or pressed the thin armor into the inside of the vehicle, which led to damage to equipment or the death of the crew.
An armor-piercing projectile is a kinetic means of hitting a target - that is, it ensures defeat due to the energy of the impact of the projectile, and not the explosion. In armor-piercing projectiles, energy is actually concentrated at its tip, where a sufficiently large pressure is created on a small area of the surface, and the load significantly exceeds the tensile strength of the armor material. As a result, this leads to the introduction of the projectile into the armor and its penetration. Kinetic munitions were the first mass-produced anti-tank weapon that was commercially used in various wars. The impact energy of the projectile depends on the mass and its speed at the moment of contact with the target. The mechanical strength, the density of the material of an armor-piercing projectile are also critical factors on which its effectiveness depends. For many years of wars, various types of armor-piercing shells have been developed, differing in design, and for more than a hundred years there has been a constant improvement of both shells and the armor of tanks and armored vehicles.
The first armor-piercing projectiles were an all-steel solid projectile (blank) that pierced armor with an impact force (approximately equal to the caliber of the projectile in thickness)
Then the design began to get more complicated and for a long time the following scheme became popular: a rod / core made of hard hardened alloy steel covered in a shell of soft metal (lead or mild steel), or light alloy. The soft shell was needed to reduce wear on the gun barrel, and also because it was not practical to make the entire projectile from hardened alloy steel. The soft shell was crushed when hitting an inclined barrier, thereby preventing the projectile from ricocheting / slipping on the armor. The shell can also serve as a fairing at the same time (depending on the shape) that reduces air resistance during the flight of the projectile.
Another design of the projectile involves the absence of a shell and only the presence of a special soft metal cap as a projectile tip for aerodynamics and to prevent ricochet when hitting sloped armor.
The device of sub-caliber armor-piercing shells
The projectile is called sub-caliber because the caliber (diameter) of its combat / armor-piercing part is 3 less than the caliber of the gun (a - coil, b - streamlined). 1 - ballistic tip, 2 - pallet, 3 - armor-piercing core / armor-piercing part, 4 - tracer, 5 - plastic tip.
The projectile has rings around it made of soft metal, which are called leading belts. They serve to center the projectile in the barrel and obturate the barrel. Obturation is the sealing of the barrel bore when a gun (or a weapon in general) is fired, which prevents the powder gases (accelerating the projectile) from breaking through into the gap between the projectile itself and the barrel. Thus, the energy of the powder gases is not lost and is transferred to the projectile to the maximum possible extent.
Left- the dependence of the thickness of the armored barrier on its angle of inclination. A plate of thickness B1 inclined at some angle, a has the same resistance as a thicker plate of thickness B2 at right angles to the movement of the projectile. It can be seen that the path that the projectile must pierce increases with the increase in the slope of the armor.
On right- blunt projectiles A and B at the time of contact with sloping armor. Below - sharp-headed arrow-shaped projectile. Due to the special shape of projectile B, its good engagement (biting) on sloping armor is visible, which prevents ricochet. The pointed projectile is less prone to ricochet due to its sharp shape and very high contact pressure upon impact with armor.
The damaging factors when such projectiles hit the target are scattered on high speed fragments and fragments of armor from its inner side, as well as the flying projectile itself or its parts. Particularly affected equipment located on the trajectory of breaking through the armor. In addition, due to the high temperature of the projectile and its fragments, as well as the presence of a large amount of flammable objects and materials inside the tank or armored vehicle, the risk of fire is very high. The image below shows how this happens:
A relatively soft projectile body is visible, crushed during impact and a hard-alloy core that penetrates armor. On the right, a stream of high-velocity fragments is visible from the inside of the armor as one of the main damaging factors. In all modern tanks there is a tendency for the most dense placement of internal equipment and crew to reduce the size and weight of tanks. The flip side of this coin is that if the armor is penetrated, it is almost guaranteed that some important equipment will be damaged or a crew member will be injured. And even if the tank is not destroyed, it usually becomes incapacitated. On modern tanks and armored vehicles, a non-combustible anti-fragmentation lining is installed on the inside of the armor. As a rule, this is a material based on Kevlar or other high-strength materials. Although it does not protect against the core of the projectile itself, it retains some of the armor fragments, thereby reducing the damage done and increasing the survivability of the vehicle and crew.
Above, on the example of an armored vehicle, one can see the armored effect of the projectile and fragments with and without the lining installed. On the left, fragments and the shell itself that pierced the armor are visible. On the right, the installed lining holds most of the armor fragments (but not the projectile itself), thereby reducing damage.
Even more efficient view shells are chamber shells. Chamber armor-piercing projectiles are distinguished by the presence of a chamber (cavity) inside the projectile filled with explosives and a delayed detonator. After penetrating the armor, the projectile explodes inside the object, thereby significantly increasing the damage dealt by fragments and a shock wave in a closed volume. In fact, this is an armor-piercing landmine.
One of the simple examples of a chamber projectile scheme
1 - soft ballistic shell, 2 - armor-piercing steel, 3 - explosive charge, 4 - bottom detonator, working with slowdown, 5 - front and rear leading belts (shoulders).
Chamber shells are not used today as anti-tank shells, since their design is weakened by an internal cavity with explosives and is not designed to penetrate thick armor, that is, a shell tank caliber(105 - 125 mm) will simply collapse in a collision with a modern frontal tank armor(equivalent to 400 - 600 mm of armor and above). Such shells were widely used during the Second World War, since their caliber was comparable to the thickness of the armor of some tanks of that time. In naval battles of the past, chamber shells were used from large caliber 203 mm and up to a monstrous 460 mm (battleship of the Yamato series), which could well penetrate thick ship steel armor comparable in thickness to their caliber (300 - 500 mm), or a layer of reinforced concrete and stone several meters.
Modern armor-piercing ammunition
Despite the fact that various types of anti-tank missiles were developed after the Second World War, armor-piercing ammunition remains one of the main anti-tank weapons. Despite the indisputable advantages of missiles (mobility, accuracy, homing capabilities, etc.), armor-piercing shells also have their advantages.
Their main advantage lies in the simplicity of design and, accordingly, production, which affects the lower price of the product.
In addition, an armor-piercing projectile, unlike an anti-tank missile, has a very high approach speed to the target (from 1600 m / s and above), it is impossible to “leave” it by maneuvering in time or hiding in a shelter (in a certain sense, when launching a rocket, such there is a possibility). In addition, an anti-tank projectile does not require the need to keep the target on sight, like many, though not all, ATGMs.
It is also impossible to create radio-electronic interference against an armor-piercing projectile due to the fact that it simply does not contain any electronic devices. In the case of anti-tank missiles, this is possible, such complexes as Shtora, Afghanit or Zaslon * are created specifically for this.
A modern armor-piercing projectile widely used in most countries of the world is actually a long rod made of a high-strength metal (tungsten or depleted uranium) or composite (tungsten carbide) alloy and rushing to the target at a speed of 1500 to 1800 m / s and higher. The rod at the end has stabilizers called plumage. The projectile is abbreviated as BOPS (Armor Piercing Feathered Sub-caliber Projectile). You can also just call it BPS (Armor Piercing Sub-caliber Projectile).
Almost all modern armor-piercing ammunition shells have the so-called. "Plumage" - tail flight stabilizers. The reason for the appearance of feathered shells lies in the fact that the shells of the old scheme described above after the Second World War exhausted their potential. It was necessary to lengthen the shells for greater efficiency, but they lost stability at a large length. One of the reasons for the loss of stability was their rotation in flight (since most of the guns were rifling and imparted rotational motion to the projectiles). The strength of the materials of that time did not allow the creation of long projectiles with sufficient strength to penetrate thick composite (puff) armor. The projectile was easier to stabilize not by rotation, but by plumage. An important role in the appearance of plumage was also played by the appearance of smooth-bore guns, the shells of which could be accelerated to higher speeds than when using rifled guns, and the problem of stabilization in which began to be solved with the help of plumage (we will touch on the topic of rifled and smooth-bore guns in the next material).
Especially important role materials play in armor-piercing shells. Tungsten carbide** (composite material) has a density of 15.77 g/cm3, which is almost twice that of steel. It has great hardness, wear resistance and melting point (about 2900 C). IN Lately heavier alloys based on tungsten and uranium have become especially widespread. Tungsten or depleted uranium has a very high density, which is almost 2.5 times higher than that of steel (19.25 and 19.1 g/cm3 versus 7.8 g/cm3 for steel) and, accordingly, greater mass and kinetic energy while maintaining minimal dimensions. Also, their mechanical strength (especially in bending) is higher than that of composite tungsten carbide. Thanks to these qualities, it is possible to concentrate more energy in a smaller volume of the projectile, that is, to increase the density of its kinetic energy. Also, these alloys have tremendous strength and hardness compared to even the strongest existing armor or specialty steels.
The projectile is called sub-caliber because the caliber (diameter) of its combat / armor-piercing part is less than the caliber of the gun. Typically, the diameter of such a core is 20 - 36 mm. Recently, projectile developers have been trying to reduce the diameter of the core and increase its length, if possible, maintain or increase mass, reduce drag during flight and, as a result, increase contact pressure at the point of impact with armor.
Uranium ammunition has 10 - 15% greater penetration with the same dimensions due to an interesting feature of the alloy called self-sharpening. The scientific term for this process is "ablative self-sharpening". As a tungsten projectile passes through the armor, its tip is deformed and flattened due to the enormous drag. When flattened, its contact area increases, which further increases the resistance to movement and, as a result, penetration suffers. When a uranium projectile passes through the armor at speeds greater than 1600 m/sec, its tip does not deform or flatten, but simply breaks down parallel to the movement of the projectile, that is, it peels off in parts and thus the rod always remains sharp.
In addition to the already listed damaging factors of armor-piercing projectiles, modern BPSs have a high incendiary ability when penetrating armor. This ability is called pyrophoricity - that is, self-ignition of projectile particles after breaking through armor ***.
125 mm BOPS BM-42 "Mango"
The design is a tungsten alloy core in a steel shell. Visible stabilizers at the end of the projectile (empennage). The white circle around the stem is the obturator. On the right, the BPS is equipped (drowned) inside the powder charge and in this form is delivered in tank forces. On the left is the second powder charge with a fuse and a metal pan. As you can see, the whole shot is divided into two parts, and only in this form it is placed in the automatic loader of tanks of the USSR / RF (T-64, 72, 80, 90). That is, first the loading mechanism sends the BPS with the first charge, and then the second charge.
The photo below shows parts of the obturator at the moment of separation from the rod in flight. A burning tracer is visible at the bottom of the rod.
Interesting Facts
*The Russian Shtora system was designed to protect tanks from anti-tank guided missiles. The system determines that a laser beam is aimed at the tank, determines the direction of the laser source, and sends a signal to the crew. The crew can maneuver or hide the car in a shelter. The system is also connected to starting device smoke rockets that create a cloud that reflects optical and laser radiation, thereby knocking down the ATGM missile from the target. There is also the interaction of "Curtains" with searchlights - emitters that can interfere with the device of an anti-tank missile when directed at it. The effectiveness of the Shtora system against various latest-generation ATGMs is still in question. There are controversial opinions on this matter, but, as they say, its presence is better than its complete absence. The last Russian tank "Armata" has a different system - the so-called. system of complex active protection "Afganit", which, according to the developers, is capable of intercepting not only anti-tank missiles, but also armor-piercing shells flying at speeds up to 1700 m/s (in the future it is planned to increase this figure to 2000 m/s). In turn, the Ukrainian development "Barrier" operates on the principle of detonating ammunition on the side of an attacking projectile (rocket) and giving it a powerful impulse in the form of a shock wave and fragments. Thus, the projectile or missile deviates from the originally given trajectory, and is destroyed before meeting the target (or rather, its target). Judging by technical specifications, this system can be most effective against RPGs and ATGMs.
**Tungsten carbide is used not only for the manufacture of shells, but also for the manufacture of heavy-duty tools for working with extra hard steels and alloys. For example, an alloy called "Pobedit" (from the word "Victory") was developed in the USSR in 1929. It is a solid homogeneous mixture/alloy of tungsten carbide and cobalt in a ratio of 90:10. Products are obtained by powder metallurgy. Powder metallurgy is the process of obtaining metal powders and manufacturing various high-strength products from them with pre-calculated mechanical, physical, magnetic, and other properties. This process makes it possible to obtain products from mixtures of metals and non-metals that simply cannot be joined by other methods, such as fusion or welding. The mixture of powders is loaded into the mold of the future product. One of the powders is a binding matrix (something like cement), which will firmly connect all the smallest particles / grains of the powder to each other. Examples are nickel and cobalt powders. The mixture is pressed in special presses under pressure from 300 to 10,000 atmospheres. The mixture is then heated to a high temperature (70 to 90% of the melting point of the binder metal). As a result, the mixture becomes denser and the bond between the grains is strengthened.
*** Pyrophoricity is the ability of a solid material to self-ignite in air in the absence of heating and being in a finely divided state. The property can manifest itself upon impact or friction. One material that satisfies this requirement well is depleted uranium. When breaking through the armor, part of the core will just be in a finely divided state. Add to this the same high temperature at the point of penetration of the armor, the impact itself and the friction of many particles, and we get ideal conditions for ignition. Special additives are also added to tungsten alloys of shells to make them more pyrophoric. How the simplest example Pyrophoricity in everyday life can lead to silicon lighters which are made of an alloy of cerium metal.
) and 40 tons ("Puma", "Namer"). In this regard, overcoming the armor protection of these vehicles is a serious problem for anti-tank ammunition, which include armor-piercing and cumulative projectiles, rockets and rocket-propelled grenades with kinetic and cumulative warheads, as well as striking elements with an impact core.
Among them, armor-piercing sub-caliber shells and missiles with a kinetic warhead are the most effective. Possessing high armor penetration, they differ from other anti-tank munitions in their high approach speed, low sensitivity to the effects of dynamic protection, the relative independence of the weapon guidance system from natural / artificial interference, and low cost. Moreover, these types of anti-tank munitions can be guaranteed to overcome the active protection system of armored vehicles, which is increasingly becoming widespread as a front line for intercepting striking elements.
Currently, only armor-piercing sub-caliber shells have been adopted for service. They are fired mainly from smooth-bore guns of small (30-57 mm), medium (76-125 mm) and large (140-152 mm) calibers. The projectile consists of a two-bearing leading device, the diameter of which coincides with the diameter of the barrel bore, consisting of sections separated after departure from the barrel, and a striking element - an armor-piercing rod, in the bow of which a ballistic tip is installed, in the tail - an aerodynamic stabilizer and a tracer charge.
As the material of the armor-piercing rod, ceramics based on tungsten carbide (density 15.77 g / cc), as well as metal alloys based on uranium (density 19.04 g / cc) or tungsten (density 19.1 g / cc) are used. cc). The diameter of the armor-piercing rod ranges from 30 mm (obsolete models) to 20 mm (modern models). The higher the density of the rod material and the smaller the diameter, the greater the specific pressure exerted by the projectile on the armor at the point of its contact with the front end of the rod.
Metal rods have much greater bending strength than ceramic ones, which is very important when the projectile interacts with active protection shrapnel elements or explosive dynamic protection plates. At the same time, the uranium alloy, despite its somewhat lower density, has an advantage over tungsten - the armor penetration of the first is 15-20 percent greater due to the ablative self-sharpening of the rod in the process of penetrating armor, starting from an impact speed of 1600 m / s, provided by modern cannon shots.
The tungsten alloy begins to exhibit ablative self-sharpening starting at 2000 m/s, requiring new ways to accelerate projectiles. At a lower speed, the front end of the rod flattens out, increasing the penetration channel and reducing the penetration depth of the rod into the armor.
Along with this advantage, the uranium alloy has one drawback - in the event of a nuclear conflict, neutron irradiation penetrating the tank induces secondary radiation in uranium that affects the crew. Therefore, in the arsenal of armor-piercing shells, it is necessary to have models with rods made of both uranium and tungsten alloys, designed for two types of military operations.
Uranium and tungsten alloys also have pyrophoricity - ignition of heated metal dust particles in air after breaking through the armor, which serves as an additional damaging factor. The specified property manifests itself in them, starting from the same speeds as the ablative self-sharpening. Another damaging factor is heavy metal dust, which has a negative biological effect on the crew of enemy tanks.
The leading device is made of aluminum alloy or carbon fiber, the ballistic tip and aerodynamic stabilizer are made of steel. The lead device serves to accelerate the projectile in the bore, after which it is discarded, so its weight must be minimized by using composite materials instead of aluminum alloy. The aerodynamic stabilizer is subjected to thermal effects from the powder gases generated during the combustion of the powder charge, which can affect the accuracy of shooting, and therefore it is made of heat-resistant steel.
The armor penetration of kinetic projectiles and missiles is defined as the thickness of a homogeneous steel plate, set perpendicular to the axis of the projectile's flight, or at a certain angle. In the latter case, the reduced penetration of the equivalent thickness of the plate is ahead of the penetration of the plate, installed along the normal, due to the large specific loads at the entrance and exit of the armor-piercing rod into / out of the inclined armor.
Upon entering the sloping armor, the projectile forms a characteristic roller above the penetration channel. The blades of the aerodynamic stabilizer, collapsing, leave a characteristic "star" on the armor, by the number of rays of which it is possible to determine the belonging of the projectile (Russian - five rays). In the process of breaking through the armor, the rod is intensively ground off and significantly reduces its length. When leaving the armor, it elastically bends and changes the direction of its movement.
A characteristic representative of the penultimate generation of armor-piercing artillery ammunition is the Russian 125-mm separate-loading round 3BM19, which includes a 4Zh63 cartridge case with the main propellant charge and a 3BM44M cartridge case containing an additional propellant charge and the 3BM42M "Lekalo" sub-caliber projectile itself. Designed for use in the 2A46M1 gun and newer modifications. The dimensions of the shot allow it to be placed only in modified versions of the automatic loader.
The ceramic core of the projectile is made of tungsten carbide, placed in a steel protective case. The leading device is made of carbon fiber. As the material of the sleeves (except for the steel pallet of the main propellant charge), cardboard impregnated with trinitrotoluene was used. The length of the cartridge case with the projectile is 740 mm, the length of the projectile is 730 mm, the length of the armor-piercing rod is 570 mm, and the diameter is 22 mm. The weight of the shot is 20.3 kg, the cartridge case with the projectile is 10.7 kg, the armor-piercing rod is 4.75 kg. The initial speed of the projectile is 1750 m / s, armor penetration at a distance of 2000 meters along the normal is 650 mm of homogeneous steel.
The latest generation of Russian armor-piercing artillery ammunition is represented by 125-mm separate-loading rounds 3VBM22 and 3VBM23, equipped with two types sub-caliber shells- respectively 3VBM59 "Lead-1" with an armor-piercing rod made of a tungsten alloy and 3VBM60 with an armor-piercing rod made of a uranium alloy. The main propellant charge is loaded into the 4Zh96 "Ozon-T" cartridge case.
The dimensions of the new projectiles coincide with the dimensions of the Lekalo projectile. Their weight is increased to 5 kg due to the greater density of the rod material. To disperse heavy projectiles in the barrel, a more voluminous main propellant charge is used, which limits the use of shots, including Lead-1 and Lead-2 projectiles, only new cannon 2A82, which has an enlarged charging chamber. Armor penetration at a distance of 2000 meters along the normal can be estimated as 700 and 800 mm of homogeneous steel, respectively.
Unfortunately, the Lekalo, Lead-1 and Lead-2 projectiles have a significant design flaw in the form of centering screws located along the perimeter of the supporting surfaces of the leading devices (protrusions visible in the figure on the front supporting surface and points on the surface of the sleeve ). Centering screws are used for stable management projectile in the bore, but their heads at the same time have a destructive effect on the surface of the channel.
In foreign designs of the latest generation, precision obturator rings are used instead of screws, which reduces barrel wear by a factor of five when fired with an armor-piercing sub-caliber projectile.
The previous generation of foreign armor-piercing sub-caliber projectiles is represented by the German DM63, which is part of a unitary shot for the standard 120 mm NATO smoothbore gun. Armor-piercing rod is made of tungsten alloy. The weight of the shot is 21.4 kg, the weight of the projectile is 8.35 kg, the weight of the armor-piercing rod is 5 kg. Shot length is 982 mm, projectile length is 745 mm, core length is 570 mm, diameter is 22 mm. When firing from a cannon with a barrel length of 55 calibers, the initial speed is 1730 m / s, the speed drop on the flight path is declared at the level of 55 m / s for every 1000 meters. Armor penetration at a distance of 2000 meters normal is estimated at 700 mm of homogeneous steel.
The latest generation of foreign armor-piercing sub-caliber projectiles includes the American M829A3, which is also part of the unitary shot for the standard 120-mm NATO smoothbore gun. Unlike the D63 projectile, the armor-piercing rod of the M829A3 projectile is made of a uranium alloy. The weight of the shot is 22.3 kg, the weight of the projectile is 10 kg, the weight of the armor-piercing rod is 6 kg. Shot length is 982 mm, projectile length is 924 mm, core length is 800 mm. When firing from a cannon with a barrel length of 55 calibers, the initial speed is 1640 m/s, the speed drop is declared at the level of 59.5 m/s for every 1000 meters. Armor penetration at a distance of 2000 meters is estimated at 850 mm homogeneous steel.
When comparing the latest generation of Russian and American sub-caliber projectiles equipped with armor-piercing uranium alloy cores, a difference in the level of armor penetration is visible, to a greater extent due to the degree of elongation of their striking elements - 26-fold for the lead of the Lead-2 projectile and 37-fold for the rod projectile М829А3. In the latter case, a quarter greater specific load is provided at the point of contact between the rod and armor. In general, the dependence of the armor penetration value of shells on the speed, weight and elongation of their striking elements is shown in the following diagram.
An obstacle to increasing the elongation of the striking element and, consequently, the armor penetration of Russian projectiles is the automatic loader device, first implemented in 1964 in the Soviet T-64 tank and repeated in all subsequent models of domestic tanks, which provides for a horizontal arrangement of projectiles in a conveyor, the diameter of which is not may exceed the internal width of the hull, equal to two meters. Taking into account the case diameter of Russian shells, their length is limited to 740 mm, which is 182 mm less than the length of American shells.
In order to achieve parity with the cannon weapons of a potential enemy for our tank building, the priority for the future is the transition to unitary shots, located vertically in an automatic loader, the shells of which have a length of at least 924 mm.
Other ways to increase the effectiveness of traditional armor-piercing projectiles without increasing the caliber of guns have practically exhausted themselves due to restrictions on the pressure in the barrel chamber developed during the combustion of a powder charge, due to the strength of weapon steel. When moving to a larger caliber, the size of the shots becomes comparable to the width of the tank hull, forcing the shells to be placed in the aft niche of the turret with increased dimensions and a low degree of protection. For comparison, the photo shows a shot of 140 mm caliber and a length of 1485 mm next to a mock shot of a 120 mm caliber and a length of 982 mm.
In this regard, in the United States, within the framework of the MRM (Mid Range Munition) program, active missiles MRM-KE with kinetic warhead and MRM-CE with HEAT warhead. They are loaded into the cartridge case of a standard 120-mm cannon shot with a propellant charge of gunpowder. In the caliber body of shells are located radar head homing (GOS), striking element (armor-piercing rod or shaped charge), impulse trajectory correction engines, booster rocket engine and tail unit. The weight of one projectile is 18 kg, the weight of the armor-piercing rod is 3.7 kg. The initial speed at the level of the muzzle is 1100 m/s, after the completion of the accelerating engine, it increases to 1650 m/s.
Even more impressive performance has been achieved in the framework of the creation of an anti-tank kinetic rocket CKEM (Compact Kinetic Energy Missile), whose length is 1500 mm, weight 45 kg. The rocket is launched from a transport and launch container using a powder charge, after which the rocket is accelerated by an accelerating solid-propellant engine to a speed of almost 2000 m / s (Mach 6.5) in 0.5 seconds.
The subsequent ballistic flight of the rocket is carried out under the control of the radar seeker and aerodynamic rudders with stabilization in the air using the tail unit. The minimum effective firing range is 400 meters. The kinetic energy of the damaging element - armor-piercing rod at the end of jet acceleration reaches 10 mJ.
During the tests of the MRM-KE projectiles and the CKEM rocket, the main drawback of their design was revealed - unlike sub-caliber armor-piercing projectiles with a separating leading device, the inertia flight of the striking elements of a caliber projectile and a kinetic missile is carried out assembled with a body of large cross-section and increased aerodynamic resistance, which causes a significant drop in speed on the trajectory and a decrease in the effective firing range. In addition, the radar seeker, impulse correction engines and aerodynamic rudders have a low weight perfection, which makes it necessary to reduce the weight of the armor-piercing rod, which negatively affects its penetration.
The way out of this situation is seen in the transition to the separation in flight of the caliber body of the projectile / rocket and the armor-piercing rod after the completion of the rocket engine, by analogy with the separation of the leading device and the armor-piercing rod, which are part of the sub-caliber projectiles, after their departure from the barrel. Separation can be carried out with the help of an expelling powder charge, which is triggered at the end of the accelerating section of the flight. Reduced-size seeker should be located directly in the ballistic tip of the rod, while the flight vector control must be implemented on new principles.
A similar technical problem was solved as part of the BLAM (Barrel Launched Adaptive Munition) project to create small-caliber guided artillery shells, performed at the Adaptive Aerostructures Laboratory AAL (Adaptive Aerostructures Laboratory) of Auburn University by order of the US Air Force. The aim of the project was to create a compact homing system that combines a target detector, a controlled aerodynamic surface and its drive in one volume.
The developers decided to change the direction of flight by deflecting the head of the projectile by a small angle. At supersonic speed, a fraction of a degree deviation is enough to create a force capable of implementing a control action. A simple technical solution was proposed - the ballistic tip of the projectile rests on a spherical surface, which plays the role of a ball bearing, several piezoceramic rods are used to drive the tip, arranged in a circle at an angle to the longitudinal axis. Changing their length depending on the applied voltage, the rods deflect the tip of the projectile to the desired angle and with the desired frequency.
The calculations determined the strength requirements for the control system:
- accelerating acceleration up to 20,000 g;
- acceleration on the trajectory up to 5,000 g;
- projectile speed up to 5000 m / s;
— tip deflection angle up to 0.12 degrees;
— drive actuation frequency up to 200 Hz;
- drive power 0.028 watts.
Recent advances in the miniaturization of infrared radiation sensors, laser accelerometers, computing processors and lithium-ion power supplies resistant to high accelerations (such as electronic devices for guided missiles - American and Russian), make it possible in the period up to 2020 to create and adopt kinetic projectiles and missiles with an initial flight speed of more than two kilometers per second, which will significantly increase the effectiveness of anti-tank munitions, and also make it possible to abandon the use of uranium as part of their striking elements.
IN game world of Tanks vehicles can be equipped with different types shells, such as armor-piercing, sub-caliber, cumulative and high-explosive fragmentation. In this article, we will consider the features of the action of each of these shells, the history of their invention and use, the pros and cons of their use in a historical context. The most common and, in most cases, regular shells on the vast majority of vehicles in the game are armor-piercing shells(BB) caliber device or sharp-headed.
According to the Military Encyclopedia of Ivan Sytin, the idea of the prototype of the current armor-piercing shells belongs to the officer of the Italian fleet Bettolo, who in 1877 proposed using the so-called " bottom shock tube for armor-piercing shells"(Before that, the shells were either not equipped at all, or the explosion of the powder charge was calculated on heating the head of the projectile when it hit the armor, which, however, was far from always justified). After breaking through the armor, the damaging effect is provided by shell fragments heated to a high temperature, and armor fragments. During the Second World War, shells of this type were easy to manufacture, reliable, had a fairly high penetration, and worked well against homogeneous armor. But there was also a minus - on the inclined armor, the projectile could ricochet. The thicker the armor, the more armor fragments are formed when pierced by such a projectile, and the higher the lethal force. 
The animation below illustrates the action of a chamber sharp-headed armor-piercing projectile. It is similar to armor-piercing pointed projectile, however, in the back there is a cavity (chamber) with a bursting charge of TNT, as well as a bottom fuse. After breaking through the armor, the projectile explodes, hitting the crew and equipment of the tank. In general, this projectile retained most of the advantages and disadvantages of the AR projectile, featuring a significantly higher armor effect and slightly lower armor penetration (due to the lower weight and strength of the projectile). During the War, the bottom shell fuses were not perfect enough, which sometimes led to a premature explosion of the shell before penetrating the armor, or to the failure of the fuse after penetration, but the crew, in case of penetration, rarely became easier from this.
Sub-caliber projectile(BP) has a rather complex structure and consists of two main parts - armor-piercing core and pallet. The task of the pallet, made of mild steel, is to accelerate the projectile in the bore. When the projectile hits the target, the pallet is crushed, and the heavy and hard sharp-headed core made of tungsten carbide pierces the armor.
The projectile does not have a bursting charge, ensuring that the target is hit by core fragments and armor fragments heated to high temperatures. Sub-caliber projectiles have a significantly lower weight compared to conventional armor-piercing projectiles, which allows them to accelerate in the gun barrel to significantly higher speeds. As a result, the penetration of sub-caliber shells is significantly higher. The use of sub-caliber shells made it possible to significantly increase the armor penetration of the existing guns, which made it possible to hit more modern, well-armored armored vehicles even with outdated guns.
At the same time, sub-caliber shells have a number of disadvantages. Their shape resembled a coil (there were shells of this type and streamlined shape, but they were much less common), which greatly worsened the ballistics of the projectile, in addition, the light projectile quickly lost speed; as a result, at long distances, the armor penetration of sub-caliber shells dropped dramatically, turning out to be even lower than that of classic armor-piercing shells. During the Second World War, sabots did not work well on sloped armor, because under the influence of bending loads, the hard but brittle core easily broke. The armor-piercing effect of such shells was inferior to armor-piercing caliber shells. Sub-caliber projectiles of small caliber were ineffective against armored vehicles that had protective shields made of thin steel. These shells were expensive and difficult to manufacture, and most importantly, scarce tungsten was used in their manufacture.
As a result, the number of sub-caliber shells in the ammunition load of guns during the war years was small, they were allowed to be used only to destroy heavily armored targets at short distances. The German army was the first to use sub-caliber shells in small quantities in 1940 during the fighting in France. In 1941, faced with heavily armored Soviet tanks, the Germans switched to the widespread use of sub-caliber shells, which significantly increased the anti-tank capabilities of their artillery and tanks. However, the shortage of tungsten limited the release of shells of this type; as a result, in 1944, the production of German sub-caliber shells was discontinued, while most of the shells fired during the war years had a small caliber (37-50 mm).
In an attempt to get around the problem of tungsten shortages, the Germans produced Pzgr.40(C) sub-caliber shells with a hardened steel core and surrogate Pzgr.40(W) shells with an ordinary steel core. In the USSR, a fairly mass production of sub-caliber shells, created on the basis of captured German ones, began at the beginning of 1943, and most of the shells produced were 45 mm caliber. The production of these shells is over large calibers was limited by the shortage of tungsten, and they were issued to the troops only when there was a threat of an enemy tank attack, and a report was required for each expended projectile. Also, sub-caliber shells were used to a limited extent by the British and American armies in the second half of the war.
HEAT projectile(CS).
The operating principle of this armor-piercing ammunition differs significantly from the principle kinetic ammunition, which include conventional armor-piercing and sub-caliber shells. A cumulative projectile is a thin-walled steel projectile filled with a powerful explosive - RDX, or a mixture of TNT and RDX. At the front of the projectile, explosives have a goblet-shaped recess lined with metal (usually copper). The projectile has a sensitive head fuse. When a projectile collides with armor, an explosive is detonated. At the same time, the lining metal is melted and compressed by an explosion into a thin jet (pestle), flying forward at an extremely high speed and penetrating armor. Armored action is provided by a cumulative jet and splashes of armor metal. The hole of the HEAT projectile is small and has melted edges, which has led to a common misconception that HEAT projectiles “burn through” the armor.
The penetration of a HEAT projectile does not depend on the velocity of the projectile and is the same at all distances. Its manufacture is quite simple, the production of the projectile does not require the use of a large amount of scarce metals. The cumulative projectile can be used against infantry and artillery as a high-explosive fragmentation projectile. At the same time, cumulative shells during the war years were characterized by numerous shortcomings. The manufacturing technology of these projectiles was not sufficiently developed, as a result, their penetration was relatively low (approximately corresponded to the caliber of the projectile or slightly higher) and was characterized by instability. The rotation of the projectile at high initial speeds made it difficult to form a cumulative jet, as a result, the cumulative projectiles had a low initial velocity, a small effective range and high dispersion, which was also facilitated by the non-optimal form of the projectile head from the point of view of aerodynamics (its configuration was determined by the presence of a notch).
The big problem was the creation of a complex fuse, which should be sensitive enough to quickly undermine the projectile, but stable enough not to explode in the barrel (the USSR was able to work out such a fuse suitable for use in powerful tank and anti-tank guns, only at the end of 1944). The minimum caliber of a cumulative projectile was 75 mm, and the effectiveness of cumulative projectiles of this caliber was greatly reduced. Mass production of HEAT shells required the deployment of large-scale production of hexogen.
The most massive cumulative projectiles were used by the German army (for the first time in the summer and autumn of 1941), mainly from 75 mm caliber guns and howitzers. The Soviet army used cumulative shells, created on the basis of captured German ones, from 1942-43, including them in the ammunition of regimental guns and howitzers that had a low muzzle velocity. The British and American armies used shells of this type, mainly in heavy howitzer ammunition. Thus, in the Second World War (in contrast to the present, when improved projectiles of this type form the basis of the ammunition load of tank guns), the use of cumulative projectiles was quite limited, mainly they were considered as a means of anti-tank self-defense of guns that had low initial speeds and low armor penetration by traditional shells (regimental guns, howitzers). At the same time, all participants in the war actively used other anti-tank weapons with cumulative ammunition - grenade launchers, aerial bombs, hand grenades.
High-explosive fragmentation projectile(OF).
It was developed in the late 40s of the twentieth century in the UK to destroy enemy armored vehicles. It is a thin-walled steel or steel-cast iron projectile filled with an explosive (usually TNT or ammonite), with a head fuse. Unlike armor-piercing shells, high-explosive shells did not have a tracer. Upon hitting the target, the projectile explodes, hitting the target with fragments and a blast wave, either immediately - a fragmentation action, or with some delay (which allows the projectile to go deeper into the ground) - a high-explosive action. The projectile is intended mainly to destroy openly located and covered infantry, artillery, field shelters (trenches, wood-and-earth firing points), unarmored and lightly armored vehicles. Well-armored tanks and self-propelled guns are resistant to high-explosive fragmentation shells.
The main advantage of a high-explosive fragmentation projectile is its versatility. This type projectiles can be used effectively against the vast majority of targets. Also, the advantages include lower cost than armor-piercing and cumulative shells of the same caliber, which reduces the cost of combat operations and firing practice. In case of a direct hit in vulnerable areas (turret hatches, engine compartment radiator, knockout screens of the aft ammunition rack, etc.), HE can disable the tank. Also, the hit of large-caliber shells can cause the destruction of lightly armored vehicles, and damage to heavily armored tanks, consisting in cracking of armor plates, jamming of the turret, failure of instruments and mechanisms, injuries and contusions of the crew.