The domestic 5.45x39 cartridge is a typical example of how the “arms race” stimulates the implementation of design solutions that are usually shelved. The idea of adopting a small-caliber cartridge with optimal ballistic characteristics as the main ammunition for small automatic weapons was proposed and justified at the beginning of the twentieth century, but found practical implementation only at the end of the last century.
We are, of course, talking about the works of the outstanding domestic designer V.G. Fedorov, who back in 1913 proposed his automatic rifle chambered for a reduced caliber 6.5 mm, and in the 1930-40s. comprehensively substantiated the advantages of small-caliber small-sized ammunition at effective firing ranges. For decades, Fedorov consistently and persistently defended the ideas of small-caliber and then low-pulse ammunition, combining in his works not only a strong theoretical basis, but also rich practical material. However, for a number of reasons, including those of a purely technological nature, his work did not have practical implementation for a long time, until the notorious “arms race” factor came into play.
Intelligence reported accurately...
Intensification of work to justify the use of small-caliber cartridges for arming the army began in the late 1950s. after receiving information from abroad about American experiences with the 5.56 mm AR-15 automatic rifle and the new Remington automatic cartridge. The history of the development of 5.56x45 ammunition and its adoption in 1962 for limited supply to the US Air Force has already been described in our magazine (No. 2, 2011). It is only worth adding to it that already in 1959, Soviet designers had at their disposal two experienced American cartridges (the future M193). The history of the creation of 5.45x39 began with them, which lasted almost 10 years. Such a long period of development and fine-tuning of such a “small” ammunition is explained by the fact that the designers had to find a middle ground among many conflicting requirements and parameters of a promising cartridge. Thus, to reduce dispersion and increase the probability of hitting a target, it was necessary to reduce the recoil impulse and power, but at the same time, to increase the penetration and lethality of a bullet, on the contrary, it was necessary to increase the power of the cartridge and the mass of the bullet. On top of this, the developments had to take into account a number of new calculated values, such as effective firing range and hit probability. To conduct comprehensive tests of the new American cartridge, a kind of “hybrid” was created from the domestic cartridge case “mod. 43 years old", re-compressed for experimental 5.6 mm bullets made according to the American model. Cal barrels were made for shooting. 5.6 mm with rifling of the same steepness as in American weapons. During comparative tests of experimental 5.6 mm cartridges with domestic 7.62 mm model 43, carried out at NII-61, high instability of cal bullets was revealed. 5.6 mm. This was due not only to the length and shape of the 3.56-gram M193 bullet, but also to the steepness of the rifling. Calculated data on the ballistic characteristics of the experimental bullet, its design, lethality and penetration ability also did not allow us to draw any clear conclusions. Work on studying the small-caliber cartridge continued, but with bullets of our own design. Initially, research was focused on choosing the most effective bullet shape and design, after which the characteristics of the recoil impulse of the cartridge and the bullet's DPV were developed. In turn, this led to the development of a new type of gunpowder and the selection of its optimal weight, as well as a radical change in the dimensions of the cartridge case. To improve the aerodynamic characteristics of the bullet, its length was increased compared to the American one, and to maintain optimal weight, a steel core was introduced into its design (the presence of a steel core made it possible to further increase the bullet's penetration ability). A steel, tombac-clad (bimetallic) jacket was developed for the new bullet, which increased its strength characteristics compared to American bullets with a soft tombac jacket, which fragmented into many fragments after hitting an obstacle. As a result of the experiments, a bullet with a length of 25.55 mm and a mass of 3.4 g was developed, which received the symbol 5.45 PS.
New sleeve
At first, the 5.45-mm low-impulse cartridge used pyroxylin tubular powder of the VUfl 545 brand, but it was almost immediately replaced by varnish, the latest development of the Sf033fl brand (spheroid, burning arch thickness - 0.33 mm, phlegmatized) spherical graining with more high energy indicators and greater gravimetric density. The weight of the sample was chosen to be 1.44 g. Gunpowder brand VUfl 545 is currently used only for equipping 5.45 mm cartridges with bullets with reduced ricocheting ability - PRS. Initially, new bullets were loaded into re-compressed bimetallic machine gun casings “model. 43 years", which by that time had already been mastered in the production of domestic sports and hunting cartridges 5.6x39 and were used in the Bars hunting carbine. 
An experimental batch of about 2 million units was sent for testing to the Odessa Military District. However, when working in automatic weapons, a number of shortcomings appeared in the design of the cartridge case with a large slope and a too “thick” body. The use of new Sf033fl gunpowder in the cartridge made it possible to reduce the diameter of the cartridge case body without losing the required characteristics of the ammunition. The design of the reduced sleeve was carried out by the engineer of the development group, Lidiya Ivanovna Bulavskaya. At the stage of final testing, the new compact ammunition received the conditional index of the developer (TsNIITOCHMASH, Klimovsk) - 13MZhV. After the final fine-tuning of the bullet, carried out by cartridge production technologist Mikhail Egorovich Fedorov, it was assigned a 5.45 mm caliber, measured according to the domestic standard - by field. For some time, the new cartridge was produced with bimetallic sleeves, but at the stage of final development of the cartridge by 1967, more economical varnished steel sleeves were developed. The actual length of the cartridge case was 39.82 mm, but in the currently accepted international designation for this ammunition, the length of the cartridge case is usually rounded to 39 mm. To equip the 5.45 mm cartridge cases, a brass KV-16 igniter capsule with a diameter of 5.06 mm was used, which later received the army index 7KV1. A large team of ammunition specialists under the leadership of V.M. took part in the creation of the new ammunition. Sabelnikova.
In parallel with the experiments on the ordinary one, work was carried out to create cartridges with special bullets - tracers and reduced speed. After testing the entire complex of new small-caliber small arms of the Soviet Army - machine guns and light machine guns - the 5.45x39 cartridge received the GRAU 7N6 index and was officially adopted for service in 1974, although its mass production began in the late 1960s. Simultaneously with the 7N6, ammunition with tracer bullets (index 7T3), cartridges with reduced bullet speed (index 7U1), blanks (index 7X3) and training (index 7X4) were accepted. The production of machine gun cartridges was launched at six Soviet cartridge factories - Ulyanovsk (No. 3), Amur (No. 7), Barnaul (No. 17), Frunzensky (No. 60), Lugansk (No. 270) and Tula (No. 539).
Standard bullet
The 7N6 cartridge was equipped with a PS bullet with a conical bottom part 25.55 mm long and weighing 3.4 g. The bullet consisted of a bimetallic shell, a lead jacket and a blunt core made of grade 10 steel. There is a technological cavity between the upper end of the core and the bullet shell. The charge of gunpowder Sf033fl (since 1987 - grade SSNf 30/3.69) gives the bullet an initial speed of the order of 870-890 m/s. Subsequently, in connection with the increase in the level of target protection with personal protective equipment (PPE), the need arose to enhance the penetration ability of a conventional cal bullet. 5.45 mm, which was achieved through the use of a hardened core made of steel grades 65G, 70 or 75. A new modification of the 7N6M cartridge was adopted in 1987. The 7N6 and 7N6M cartridges do not have a special distinctive color marking. The subsequent appearance of body armor with titanium armor plates prompted the search for new ways to further increase the penetrating effect of bullets of the 5.45 mm cartridge. By 1991, specialists from the Lugansk Machine Tool Plant (No. 270) had developed a cartridge with a bullet of increased penetration (symbol of the 5.45 PP cartridge), which, after being put into service, received the GRAU 7N10 index. The bullet of the new cartridge received an elongated stamped hardened core made of steel grades 70 and 75 with a pointed top and a flat cut of the head with a diameter of about 1.8 mm. There was also a technological cavity in the head of the bullet. In addition to increasing the mass of the bullet to 3.6 g due to an increase in the length of the core, the mass of the powder charge was also slightly increased - to 1.46 g. New cartridge was put into service, but with the collapse of the USSR, the technological line for the production of 7N10 cartridges and the corresponding development rights remained in Lugansk. In this situation, Russian manufacturers urgently had to “re-develop” the 7N10 cartridge, which later resulted in a number of upgrades to the 5.45x39 cartridge, which will be discussed in our next issue.
Tracer bullets
The second main cartridge of the 5.45 mm caliber ammunition was a cartridge with a tracer bullet, which was simultaneously developed at the very early stage of experiments with small-caliber cartridges. The bullet structurally consisted of a bimetallic shell, a lead core in the head and a tracer compound with a calibration ring in the bottom. Due to the small size of the bullet, the tracer compound was placed directly into the shell without a tracer cup. To improve the incendiary effect, the composition itself was made of two components - from the main tracer composition and the incendiary initiating it. Until 1976, bullets with a length of 26.45 mm and a mass of 3.36 g were produced, which were soon replaced by shorter ones with a length of 25.32 mm and a mass of 3.2 g. Reducing the length of the bullet, without significant damage to its characteristics, allowed several reduce the length of the cylindrical leading part, which, in turn, reduced barrel wear small arms. The mass of the Sf0033fl powder charge was 1.41 g. The cartridge with a tracer bullet under the symbol 5.45 T and the GRAU 7T3 index was adopted for service in 1974. The distinctive marking of tracer ammunition was the coloring of the top of the bullet in green.
Reduced speed
Another standard 5.45 mm ammunition was a cartridge with a reduced bullet speed, which received the symbol 5.45US (cartridge index 7U1). It is designed for use with weapons equipped with a “silent and flameless firing device” - PBS. The experience of using the domestic 7.62-mm AKM assault rifle and the PBS-1 device in the army served as the basis for the development of a similar complex for the AK74 cal assault rifle. 5.45 mm. During the experimental work, various types of “silent” bullets were consistently tested along with different models of silent and flameless firing devices - first with PBS-2, then with PBS-3 and, finally, with the final version adopted for service - PBS-4. During development, designers faced a number of technological and physical properties, related both to the ammunition itself and to the weapon used for it. Small caliber and dimensions of cal ammunition. The 5.45 mm made it very difficult to create a special cartridge with optimal characteristics. On the one hand, for satisfactory operation of the PBS, it was necessary to reduce the charge (to obtain a subsonic bullet speed) and increase the mass of the bullet (to increase its lethality), and on the other hand, it was necessary to increase the mass of the powder charge to increase the effective firing range. At the same time, the difference in the length of the barrels of AK74 assault rifles, RPK74 machine guns and shortened AKS74U assault rifles made it almost impossible to create a “universal” cartridge that would work equally in all samples. In addition, it was necessary to take into account the influence of the degree of wear of a small-caliber barrel on the ballistic characteristics of the bullet. With increasing wear, the initial speed of the bullet increased, and exceeding the subsonic speed negated the “subsonic” principle of sound dampening. As a result, a compromise decision was made - to test the US cartridge only for shortened AKS74U assault rifles with their subsequent modification for the improved PBS-4 device. This measure, in turn, limited the use of PBS-4 only to modified models of machine guns and, accordingly, narrowed general distribution complex only to some special forces of law enforcement agencies - the KGB, the Ministry of Internal Affairs and the USSR Ministry of Defense. The new machine gun with the designation AKS74UB was assigned the index GRAU 6P27. Additionally, the AKS74UB could be equipped with an under-barrel silent grenade launcher BS-1M with a 30-mm cumulative incendiary grenade 7P25. This rifle-grenade launcher complex (SGK) called “Canary” was assigned the GRAU 6S1 index. Throwing a 30-mm grenade was carried out using a special blank PHS cartridge supplied from an 8-round grenade launcher magazine. In parallel with the experiments on testing the PBS, there was a constant modernization of the US cartridge.
By the end of the 1970s, the first version of the cartridge was developed, consisting of an ordinary 7N6 bullet and a reduced powder charge. The cartridge had reinforced varnish at the junction of the bullet and the cartridge case and the top of the bullet was black. Then a special bullet with a lead core and a reduced ogive radius was developed for the US cartridge. The distinctive marking of the new US cartridge model was the coloring of the bullet tip with purple varnish. However, the mass of the new bullet turned out to be insufficient for the full operation of the PBS, and in addition to the lead core, an additional weighted core made of tungsten-cobalt alloy (grade VK8) was introduced into the design. To improve the obturation of the bullet in the barrel, its diameter was increased from 5.65 mm to 5.67 mm, which is why a characteristic ledge appeared on its ogive. The total length of the bullet after modification was 24.3 mm. P-125 pistol powder weighing 0.31 g was used as a propellant charge. The production of several batches of the final version of the 7U1 cartridge was launched in the late 1980s. at the Lugansk Machine Tool Plant.
Test cartridges
For testing weapons cal. 5.45 mm VD cartridges were developed ( high pressure) and ultrasonic (reinforced charge). VD (index GRAU 7Shch3) is designed to test the strength of weapon barrels in factory conditions. This cartridge is equipped with a bullet with a steel core weighing 3.5 g and a powder charge increased to 1.52 g. The VD bullet has an enlarged leading part due to the absence of a rear cone, like a conventional PS. The distinctive marking of the VD cartridge is that the bullet is painted yellow. The cartridge with the UZ bullet is designed to test the strength of weapon locking units. As its name suggests, it has a charge of SSNf 30/3.69 gunpowder reinforced to 1.46 g. The cartridge, which received the GRAU 7Shch4 index, is equipped with a conventional PS bullet with a steel core. The distinctive marking of the UZ cartridge is a black bullet.
Model cartridges are intended for certification of ballistic weapons, testing new samples of cartridges and conducting control measurements during shooting. Sample cartridges are made from components of gross cartridges selected during mass production to meet more stringent quality and geometric parameters. Exemplary cartridges have a distinctive marking in the form of a bullet tip, painted white.
Soviet Minimi
In the second half of the twentieth century. The idea of creating a machine gun with a combined feed: from a belt and a magazine, received practical development. This concept was implemented in the Belgian FN Minimi/M249 machine gun, the Israeli Negev and the Czech Vz.52/57. In the USSR, similar developments began in the fall of 1971 at the Izhevsk Machine-Building Plant. The objective of the project, called PU (machine gun with a unified feed), was to develop, based on the standard RPK-74, a belt-fed machine gun with additional opportunity using store-bought food and increasing the efficiency of the basic sample by one and a half times. Well-known design engineers took part in the work: Yu.K. Alexandrov, V.M. Kalashnikov, M.E. Dragunov, A.I. Nesterov. The drawings of the first prototype were ready in 1973, and in the spring of 1974, preliminary tests of the first model of the experimental PU machine gun were carried out at the Izhmash training ground. In the same year, the prototype was transferred to TsNIITOCHMASH for testing. The development was called “Poplin”. In the course of subsequent work, several models of machine guns with belt-magazine feed were developed, which were tested at TsNIITOCHMASH and at the training ground of the Ministry of Defense. Several versions of metal belts with a capacity of 200 rounds were developed for experimental machine guns. The tape was placed in a duralumin box, which was attached from below to the receiver. The machine gun was developed under standard stores from RPK-74 and AK-74, but in the course of work on the “Poplin” topic, high-capacity magazines were developed - a disk magazine for 100 rounds (designed by V.V. Kamzolov) and a drum MZO (designed by V.N. Paranin). The last experimental model of the machine gun was assembled in 1978, but the topic was soon closed. According to the military, belt feeding, along with increasing the combat rate of fire, still increases the weight and dimensions of machine guns. Options for machine guns with combined power supply have a complex design of the feed unit and reduced reliability due to differences in the amount of energy required for reloading with belt and magazine power. Later, based on the results of the “Poplin” theme, a removable SPU tape feeder was developed, which made it possible to use belt feed for standard RPK machine guns and AK assault rifles. The SPU consisted of a metal belt, a box and a tape feed mechanism driven by the bolt frame. However, this development was also not developed due to the complexity of the design and the large amount of adjustment of components.
Single and training
At the end of the 1970s. to simulate the sound of a shot when firing from a standard weapon cal. 5.45-mm designers TsNII TOC MASH V.I. Volkov and B.A. Johansen developed a blank cartridge. At the experimental stage, a blank cartridge with an elongated barrel compressed by a star was tested. However, subsequently preference was given to cartridges with a conventional sleeve and a plastic hollow bullet white. This cartridge was adopted for service under the designation GRAU 7X3. A blank cartridge is used together with a special muzzle sleeve, which provides the required level of pressure of the powder gases when fired and guaranteed destruction of the plastic “bullet”. Until the 1980s A violet sealant varnish was applied to the junction of the cartridge case and the blank cartridge bullet; later, red varnish was used.
In the 1970s to teach the rules of handling weapons, a 5.45 mm training cartridge was developed (GRAU index 7X4). This ammunition, developed by TsNIITOCHMASH designer V.I. Volkov, consists of a standard cartridge case with a cooled primer and a regular PS bullet. The training ammunition has reinforced bullet retention in the cartridge case and four longitudinal grooves on the case body. No sealant varnish or distinctive color markings were applied to the training cartridge.
IN Soviet period nomenclature of cartridges cal. The 5.45 mm was much more modest compared to the 7.62 mm cartridge mod. 43 years old. This caliber did not have cartridges with incendiary and armor-piercing incendiary bullets. This was due to the small internal volume of the bullet, which did not allow the placement of “oversized” elements of incendiary systems and any effective amount of initiating compounds.
5.6x45 "Biathlon"
A separate bright episode in national history small-caliber intermediate ammunition flashed a 5.6-mm sports cartridge "Biathlon". Since the mid-1960s. In parallel with the development of the 5.45-mm machine gun cartridge, work began in the USSR on the creation of small-caliber sports ammunition and a sports rifle. As in the case of the 5.45-mm automatic cartridge, the cartridge case of the 7.62-mm automatic cartridge “model. 43 years old." But, unlike military ammunition, the casing of the sports cartridge was immediately made of brass, which is the norm for sports cartridges. The result was a fairly powerful ammunition with a 45 mm long sleeve, allowing for a fairly large powder charge, and a 25.0 mm long bullet weighing 4.93 g. The capsule had reinforced fixation using triple point punching. Using the new cartridge, Izhevsk designers Anisimov and Susloparov developed the world's first “biathlon” rifle, BI-5, with fast reloading and low recoil impulse. The release of new cartridges was carried out in small experimental batches in the late 1960s - early 1970s. Small-scale production of BI-5 rifles was established in 1973-1975. in the experimental workshop of Izhmash. At first, the cartridge and rifle were tested at intra-Union biathlon competitions, and in 1976, during the Winter Olympic Games in Innsbruck, Austria, the world premiere took place. The result exceeded all expectations: all the gold went to the Soviet team. N. Kruglov became Olympic champion in the 20 km race, and the USSR national team became the Olympic champion in the relay. The new Soviet cartridge created a real sensation, because... at that time, even standard 5.45-mm machine gun ammunition was a sealed secret for Europe, and what can we say about highly specialized sports ammunition. A year later, the world of biathlon said goodbye to powerful cartridges: in 1977, at the Congress of the International Pentathlon and Biathlon Federation, new rules were adopted, according to which, from 1978, the standard cartridge for biathlon became .22 Long Rifle, and the distance to the target was reduced to 50 m.
The farewell of Soviet biathletes to a promising rifle took place in 1977 in the Norwegian city of Wingrom. The main hero of the sprint race was the outstanding Soviet biathlete Alexander Ivanovich Tikhonov. Without making a single mistake, leaving far behind all competitors, at the final stage of the race the athlete took the rifle off his shoulder, raised it above his head and thus covered the last 300-400 meters of the distance. At the finish line, he defiantly threw his weapon into the snow, never to pick it up again. According to eyewitnesses, the King of Norway, who was present at these competitions, could hardly hold back his tears - the scene was so poignant. So Tikhonov won his last, 11th, gold medal, and thus ended the career of the domestic sports cartridge 5.6x45 “Biathlon”. IN next year The World Championship was held in Hochfilzen, Austria, but under new rules and with new cartridges. Our team returned from there without a single award.
To make it easier to equip stores with cartridges, special fast-charging clips (index 6Yu20.6) for 15 rounds were adopted. It was assumed that in conditions close to combat, a serviceman would be able to have spare ammunition, pre-loaded into clips for quickly loading stores during battle. The clip is fixed to the neck of the magazine using a special Y-shaped adapter (Index 6Yu20.7). When developing the clip, other options were tested, both with and without an adapter.
Container and marking
The packing capacity of 5.45 mm cartridges was a multiple of the capacity of a standard 30-round machine gun magazine. Initially, cartridges were packaged in cardboard boxes for 30 rounds, but in the mid-70s it was decided to switch to a simplified paper wrapper, secured with two staples. 36 paper bags with a total of 1,080 cartridges were placed in a welded metal box. Two metal boxes fit into a standard wooden box for 2,160 rounds of ammunition. A stencil was applied to the lid of the box indicating the basic data of the ammunition. In parallel with packing cartridges in paper wrappers into metal boxes, the practice was to pack 4 paper packs of 30 rounds into moisture-proof bags for 120 rounds and place these bags in a wooden box without metal boxes. With this packaging, the wooden box also contained 2,160 rounds of ammunition. Distinctive feature ammunition intended for sealing in moisture-proof bags, there was a protective oxidized coating of the primer in black, which was canceled as mandatory in 1988. For cartridges with special bullets, it is typical to apply the corresponding color stripes over stenciled inscriptions on all types of containers: paper wrappers, metal boxes and wooden boxes. For cartridges with tracer bullets, color marking is adopted in the form of a green stripe, and for cartridges with reduced bullet speed - in the form of a black and green stripe. An unusual feature that has not yet found a documented explanation is the system symbols on the closure of 5.45 mm live cartridges produced before 1982, which differed from the standard design adopted for small arms ammunition Soviet Army. According to the “traditional” system of symbols, the closure with cartridges must be sequentially marked with the caliber of the cartridge, the type of its bullet (PS, T or US) and then the type of cartridge case used (GZh - bimetallic, GS - varnished steel). For some reason, until 1982, on all types of containers of 5.45 mm cartridges, after the caliber designation, the designation of the cartridge type was applied, and only after it - the designation of the bullet type, for example, 5.45gsPS instead of 5.45PSgs.
The legend of the "center of gravity"
It is worth noting that the unusually small cartridge was received ambiguously by weapons specialists and the military. “Grandfather of Soviet machine guns” M.T. Kalashnikov was categorically against the new ammunition, arguing that for a small and long bullet, or “punch,” as Mikhail Timofeevich dubbed it at one of the ministerial meetings, it would not be possible to work out the survivability of the barrel. Indeed, initially the barrels of experimental machine guns could withstand about 2,000 shots, while the military demanded at least 10,000. It took the efforts of a separate institute, NII-13, and weapons production specialists in Kovrov and Izhevsk to solve this problem and achieve a standard barrel life of 12,000 shots. Characteristic feature 5.45 mm ammunition is characterized by a sharp loss of stability of the bullet when it hits an obstacle. The Internet resource YouTube posted an interesting video in which Americans almost point-blank are trying to shoot a TV screen at an angle with an AK-74, but the bullets ricochet off its surface and cannot break it. This property of a bullet - to sharply change its flight path when meeting an obstacle - gave rise to a persistent legend among the people (and even in the army) about a “bullet with a displaced center of gravity.” In fact, the center of gravity of the bullet, of course, lies on its longitudinal axis of symmetry (closer to the bottom) and does not “shift” anywhere. It’s just that a set of indicators such as the length and mass of the bullet, the position of its center of gravity, the ratio of the moments of inertia and the pitch of the barrel rifling are selected so that the bullet during flight is at the limit of gyroscopic stability. When hitting an obstacle, the action of two forces - gravity and the force of resistance to the environment - creates a tipping moment, at which light small-caliber bullets lose stability and turn around. This property of the bullet causes certain inconveniences when shooting “on TV”, but leads to serious injuries when hitting living targets.
Stores
The AK-74 assault rifle was fed from a box-shaped sector magazine (index 6L23) with a capacity of 30 rounds, made of orange AG-4V fiberglass. For the RPK-74 light machine guns, high-capacity box-shaped sector magazines with 45 rounds (index 6L18) were developed, which were also made from AG-4V fiberglass. Since the 1980s magazines for 30 rounds and new improved magazines for 45 rounds (index 6L26) began to be made from glass-filled polyamide PA-6 of a dark purple color, which received the nickname “plum” in the army. Since the 1970s, experimental work has been carried out with varying degrees of intensity to further increase the capacity of cartridge magazines. Options were tested for creating steel 60-round magazines with a 4-row arrangement of cartridges, followed by the restructuring of the cartridges at the neck into a standard 2-row feed. However, the practical implementation of these works took place only by 2000, when the Russian Federation a high-capacity magazine (RF Patent No. 2158890) made of black plastic was adopted.
Jun 26, 2014 Andrey aka Pulkin Donets and Dmitry aka Treshkin Adeev official IAA members
The low-impulse cartridge was a materialized expression of the spirit of intense military rivalry between the Warsaw Pact and NATO during the Cold War era. The emergence of a new ammunition-weapon complex from the main enemy required an urgent and effective response on our part. Possessing impeccable reliability, the 7.62-mm Kalashnikov AKM assault rifles, however, did not fully meet the increasing requirements of the Armed Forces for the probability of hitting the target due to increased dispersion when firing in bursts, as well as the high steepness of bullet trajectories. This was due to the fact that the large recoil impulse of the 7.62-mm machine gun cartridge model 1943 (0.78 kgf/s) did not allow even the modernized Kalashnikov assault rifle to achieve high accuracy of combat with automatic fire, especially when firing from unstable positions. Long time domestic specialists were intensively searching for ways to increase the combat effectiveness of the standard Kalashnikov assault rifle. Research has shown that the accuracy of fire from a machine gun is determined not only by the ballistic impulse of the cartridge and the recoil energy of the weapon, but also by the design characteristics of the sample itself (mass, moment of inertia, location of the centers of mass of the weapon and moving parts of the automation), as well as dynamic characteristics (rate of fire and impacts moving parts).
In the Soviet Union, the feasibility of switching to manual automatic weapons caliber smaller than the existing 7.62 mm was scientifically substantiated by V. G. Fedorov already in 1939, when he wrote that the direct shot range of an “intermediate” cartridge should be no less than that of a standard rifle cartridge. To reduce the weight and size characteristics of cartridges, he proposed reducing their caliber to 6–6.25 mm. Back in 1945, V. G. Fedorov in his work “Research further paths increasing the efficiency of shooting from small arms” argued that the most promising development of automatic small arms will only be if it develops towards reducing the caliber of cartridges. However, the official line pursued at that time by the leadership of the People's Commissariat of Armament of the USSR and the Main Artillery Directorate of the People's Commissariat of Defense of the USSR, aimed at developing a complex of small arms designed to use the 7.62-mm "intermediate" cartridge, did not take into account Fedorov's conclusions. Along with subjective factors, this was also due to objective reasons - in the Soviet Union in the mid-1940s, the arms industry enterprises lacked the technical and technological base for the production of both small-caliber combat cartridges and the weapons themselves.
And yet, the very idea of creating a more effective ammunition-weapon complex was not shelved. By the early 1960s, domestic gunsmiths had accumulated some experience in creating promising automatic infantry weapon systems, consisting of an automatic rifle and a single machine gun. They were developed for an experienced powerful 7.62-mm single automatic machine-gun cartridge designed by S. I. Vetoshkin. In this direction, Soviet designers moved parallel to our opponents, whose bitter negative experience was taken into account when carrying out subsequent work on promising small arms systems in the USSR.
The US armed forces, which had only recently rearmed with 7.62 mm M-14 automatic rifles, designed for the powerful 7.62 x 51 NATO rifle and machine gun cartridge, by this time were already reaping the sad fruits of such a hasty decision. And this, in turn, forced the American military command already in 1957 to make a fundamental decision to begin the development of automatic weapons chambered for a low-pulse cartridge, which thus became a turning point in all subsequent modern small arms. Soviet designers came to a similar conclusion about the low effectiveness of new normal rifle caliber ammunition after conducting extensive R&D. The high level of technical solution of new domestic cartridges and the resulting certain reduction in recoil impulse still did not allow us to solve the main task set for the new “ammunition-weapon” complex: to achieve an increase in effective firing range by one and a half times in relation to the standard small arms complex, designed for the 7.62 mm automatic cartridge mod. 1943.
Along with this, research was carried out in the Soviet Union in the field of the pattern of bullet dispersion depending on recoil impulses, the design of muzzle compensators, etc. New ammunition of 4.5 mm and 6.5 mm calibers was being studied, various design options for non-classical bullets and weapons under them.
Thus, in 1960–1962, engineers and designers of NII-61 V. P. Gryazev, A. G. Shipunov, D. I. Shiryaev, I. Kasyanov, O. P. Kravchenko and V. A. Petrov created low-pulse cartridges with sub-caliber feathered (arrow-shaped) bullets with leading elements that separate in flight (plastic trays). D. I. Shiryaev developed a prototype of the AO-27 assault rifle for this cartridge, which is relatively light and stable when fired with automatic fire. The greater flatness of the trajectory of the arrow-shaped bullet to a certain extent compensated for the low accuracy of the battle. However, the accuracy results shown when firing from the AO-27 turned out to be much lower than planned, so all work on similar weapons was stopped. But this did not mean a complete abandonment of the idea, since it was capable of increasing the fire efficiency of individual automatic weapons, and within a few years a new modified rifle cartridge with a swept bullet appeared, designed by the engineer of the same NII-61 V. N. Dvoryaninov for a re-barrel heavy machine gun Goryunova SGM and sniper rifle Dragunov SVD. Similar studies were also widely carried out in the United States, but the negative results shown by these ammunition during tests forced the Americans to curtail all work in this direction.
Simultaneously with the failure that ended work on the creation of a new domestic “ammunition-weapon” complex, the leadership of the USSR Ministry of Defense received information about new high-performance rifles AR 15 (XM 16), developed for the low-pulse cartridge 5.56 x 45 M 193, adopted for the experimental exploitation in the American army. Soon, military trophies from South Vietnam - the weapons and ammunition themselves - ended up in the hands of Soviet military specialists. And these facts forced the military to seriously think that the enemy was ahead of us in this area of military-technical research, since the Americans in 1961 were already conducting the final stage of military testing of a new weapon designed for a cartridge with a reduced recoil impulse. While in the Soviet Union only recently the 7.62-mm AKM assault rifle was adopted, which was already inferior to the promising AR 15 rifle in some respects.
The evolution of small arms has led to the conclusion that while maintaining the classical scheme, which uses a powder charge as an energy source for throwing bullets, reducing the caliber will increase the initial speed of the bullets. In this way, it will be possible to achieve a flat flight trajectory of bullets, reduce the weight of the weapon itself and increase the ammunition carried by the shooter (without increasing the overall weight load). The use of new designs of bullets and cartridges, new materials for bullet cores made it possible to ensure the required damaging properties of bullets of reduced calibers. At the same time, theoretical calculations showed that the characteristics of the 5.6 mm cartridge are not the same for different combat conditions. In close combat, usually offensive, when firing from unstable positions at short ranges, bullets of this caliber have maximum penetrating effect, therefore, to increase the effectiveness of hitting targets, reducing dispersion became of primary importance, which could be achieved by both reducing the power of the cartridge and reducing the impulse recoil, but at the same time this also influenced the decrease in the initial speed of the bullet. In a defensive battle, shooting was carried out at much longer ranges and mainly from stable positions, so the dispersion here is much less, and the decisive factor was the flatness of the trajectory and the penetrating effect, which could only be achieved by increasing the power of the cartridge. The contradiction between increasing the initial speed of the bullet and its mass and reducing these characteristics for different conditions The battle forced Soviet gunsmiths to look for the best option.
Therefore, in 1961 in the Soviet Union, NII-61 specialists began comprehensive research to reduce the recoil impulse of weapons and develop a new 5.6 mm cartridge with a high initial velocity based on a recompressed cartridge case of a 7.62 mm machine gun cartridge mod. 1943.
The first stage of research work, which began in the Soviet Union in 1963, to create a new “ammunition-weapon” complex was carried out on re-barrel AKM assault rifles of 5.6 mm caliber. As a result of the research, it turned out that the new 5.6 mm cartridge had a 35 percent lower recoil impulse than the 7.62 mm cartridge mod. 1943, and this made it possible to reduce the recoil energy of the weapon by 1.8 times. Research artillery test site Ministry of Defense of the USSR in the Vsevolozhsk region Leningrad region, analyzing the possibilities of using new, most optimal design schemes for small arms, indicated in his conclusion that “the most effective means improving the accuracy of an assault rifle when firing from unstable positions is to reduce the recoil impulse when firing.”
An important factor that contributed to this conclusion of our military experts was the fact that the AR 15 rifle was superior to the AKM assault rifle not only in one of the main parameters - combat accuracy, but also in the probability of hits. Thus, the most realistic way to increase the combat effectiveness of individual automatic weapons could be the adoption of a new intermediate cartridge with a reduced recoil impulse and the development of a next-generation assault rifle for it.
As a result of long-term work by a group of specialists - ammunition specialists of TsNIITOCHMASH (Klimovsk, Moscow region) under the leadership of V. M. Sabelnikov, consisting of L. I. Bulavskaya, B. V. Semin, M. E. Fedorov, P. F. Sazonov, V. . I. Volkova, V. A. Nikolaeva, E. E. Zimina, P. S. Korolev and others created a completely new domestic 5.6-mm low-pulse cartridge with a bullet with a steel core and a sleeve length of 39 mm, which received originally the name "13 MZhV". Subsequently, when the caliber designation was adopted, corresponding to the actual diameter of the barrel bore along the rifling fields - 5.45 mm, the cartridge received the GRAU index - 7 N6.
The designers managed to achieve, with a smaller bullet mass (3.42 g instead of 7.9 g for the AKM and 3.56 g for the AR 15), a reduction in the maximum permissible level of recoil impulse of machine gun cartridges (0.49 kgf/s versus 0.78 and 0. 58 kgf/s, respectively) and at the same time increase the range of a direct shot, i.e. the range at which the height of the trajectory is equal to the height of the target (440 m instead of 350 and 426 m, respectively), which, by the way, exceeded the same characteristic 7.62- mm rifle cartridge arr. 1908. The peculiarity of its bullet was that the steel core of the 5.45 mm 7 N6 cartridge had a lead jacket, and the bullet jacket was steel, clad with tombak. Such a design of the bullets ensured its better strength and greater penetrating effect than that of 5.56 x 45 M.193 cartridges. The excellent aerodynamic shape of the bullet of the new Soviet 5.45 mm cartridge contributed to its high ballistic performance (initial speed 900 m/s). In addition, its design was similar to the 7.62 mm bullet taken as a sample from a single machine gun cartridge. It also had a void in the head, which, along with the optimally selected rifling pitch for this ammunition, provided the small-caliber bullet with the same mod. 1943 lethal effect over the entire range of a direct shot. Only by the end of the 1960s were the recommendations of V. G. Fedorov finally implemented, who 30 years earlier defended his point of view on the development of intermediate small-caliber cartridges.
Improving yourself mass type small arms of the Soviet army - Kalashnikov assault rifles - was largely determined by the successful development of new 5.45 mm machine gun cartridges. For firing from the AK 74 assault rifle, 5.45 mm low-pulse cartridges mod. 1974 with steel sleeves:
- with an ordinary bullet with a steel core (PS),
With a tracer bullet (T),
- with a bullet of reduced speed (SV).
To simulate firing, blank cartridges were used (initially without a bullet, and later with a plastic bullet), which were automatically fired using a special bushing screwed onto the muzzle of the barrel, instead of a muzzle brake-compensator.
With an initial speed of 900 m/s of the AK 74 assault rifle, the bullet received a rotation speed of 4500 rpm, and the RPK 74 with an initial speed of 960 m/s - 4530 rpm). This ensured high stability of the bullet in flight, almost equivalent to the stability of a bullet from the 5.56 NATO cartridge (adopted for supply to the armies of the North Atlantic bloc only in 1980). To increase the destructive effect on manpower, the configuration of the bullet was selected so that the bullet in flight was “on the verge of stability” and lost stability when it entered a denser environment.
The new 5.45-mm cartridge 7 N6 with a flat trajectory made it possible to increase the range of a direct shot at a tall figure from 525 (for AKM) to 625 m (for AK 74). Sighting range firing from 5.45-mm machine guns was 1000 m. The effective firing range at ground targets from an assault rifle (compared to the AKM) increased to 500 m, from a machine gun - to 600 m; against airplanes, helicopters and paratroopers - from a machine gun and a machine gun - up to 500 m.
Concentrated fire on ground group targets can be carried out from machine guns and light machine guns at a range of up to 1000 m. The direct shot range of the AK 74 assault rifle was: at the chest figure - 440 m, at the running figure - 625 m; for the RPK light machine gun 74–460 and 640 m (respectively).
However, in the AK 74 assault rifle, compared to the AKM, due to a decrease in caliber, the lethal range of the bullet was reduced from 1500 to 1350 m, i.e., the ratio between the lethal range and effective firing range decreased from 3.75 to 2.7 times. Dispersion when firing from an AK 74 in short bursts from stable positions (lying from a rest or standing from a trench) at a distance of up to 800 m began to be: the total median deviation of dispersion in height - 0.48 m, the total lateral deviation - 0.64 m. Reduction in mass cartridge allowed the soldier to increase his carryable ammunition from 100 rounds of 7.62 mm caliber to 165 rounds of 5.45 mm caliber without increasing the weight of the weapon. Increasing the initial speed of the bullet, the flatness of the trajectory, and reducing the recoil impulse made it possible to raise combat effectiveness The 5.45 mm AK 74 assault rifle is 1.2–1.6 times larger than the 7.62 mm AKM assault rifle. A bullet with a steel core of the 7 N6 cartridge, when fired from an AK 74 assault rifle / RPK74 light machine gun, ensured penetration of a 5-mm steel sheet (with 80–90 percent of through penetrations) at a range of 350 m, steel helmets - at a range of 800 m, standard domestic army body armor Zh86–5 - at 550 m.
However, work to improve the “ammunition-weapon” complex in the Soviet Union did not end there. New trends in military affairs, as well as the combat use of 5.45-mm Kalashnikov AK 74 assault rifles by the Soviet army in Afghanistan, led to the need to seriously modernize both the weapon itself and the 5.45-mm cartridge. The widespread use of personal armor (in particular, body armor) in the armies of many countries in the 1980s showed that their defeat when fired from machine guns is not guaranteed. Further development of personal protective equipment, the use of body armor with plates made of durable titanium alloys sharply reduced the effectiveness of the 7 N6 bullet with a heat-strengthened core due to the imperfection of the core shape, which is not able to penetrate a titanium alloy plate even at close ranges. Therefore, Soviet gunsmith designers had to look for new ways to increase the penetrating effect of bullets from low-pulse machine gun cartridges. Already in 1986, the penetrating effect of 5.45 mm cartridges was significantly increased due to the use of a heat-strengthened core of increased hardness 7 N6 M in the bullet design: the penetration range of protected targets, in particular steel helmets, increased from 800 to 960 m, body armor with titanium plates from 20 to 200 m. Since the beginning of the 1990s, almost simultaneously with the adoption of the 5.45-mm modernized AK 74 M assault rifle (in 1991), cartridges with new bullets of increased penetration have also been introduced into service, complementing them together with a newly developed machine gun weapon system for the infantryman. So, in 1992, the core was improved again, making it more pointed and heavier. At the same initial speed, a bullet of increased penetration (PP) with a heat-strengthened core (index 7 N10) now ensured penetration of the standard domestic army body armor Zh85-T (with 40 percent of through penetrations) at a distance of 200 m, and heavy body armor Zh95-K - at range of 50 m, while a bullet with a steel core of the 5.45 mm 7 N6 M cartridge penetrated the Zh85-T body armor only at a range of 90 m, and penetration of the Zh95-K body armor was not ensured at all firing ranges. As a result, the 5.45-mm cartridge 7 N10 with a PP bullet came very close to the 7.62-mm rifle cartridge mod. 1908, and their effectiveness in breaking through barriers compared to the bullet of the 7 N6 cartridge increased 1.84 times. However, ensuring a given level of direct shot range and penetration required an increase in the power of the 5.45 mm cartridge, which definitely affected the increased recoil impulse and the fairly large dispersion of bullets when firing the AK 74. In addition, the adoption of a new cartridge with a bullet of increased penetration had a downside. The survivability of AK 74 M assault rifle barrels has sharply decreased when firing the new cartridge. Therefore, the designers had to carry out a number of research projects to improve the survivability of the barrel bore. It should be noted that the reserves of the 5.45 mm bullet in terms of increasing the effectiveness of hitting obstacles are far from being exhausted; work in this direction continues. For recent years new modifications of 5.45-mm machine gun cartridges were created and accepted for supply to the Russian Armed Forces: with an armor-piercing bullet BP (index 7 H22); with armor-piercing bullet BS (index 7 H24); cartridge with an armor-piercing tracer bullet (index 7 BT4); - modernized cartridge with a tracer bullet (index 7 T3 M); with a bullet of reduced ricocheting ability (index 5.45 PRS).
Currently, the Russian Armed Forces use the following main variants of 5.45 mm low-pulse machine gun cartridges.
5.45 mm automatic cartridge mod. 1974 with a bullet with a steel core PS (index 7 H6)
Military cartridges with bullets of all types are produced only with a bottle-shaped steel case coated with dark green varnish with a non-protruding flange and groove. The propellant charge is SFO33 spheroid powder, which has been replaced since 1989 by SSNf30/3.69 grade gunpowder.
A pointed bullet with a diameter of 5.65 mm, with an elongated head with a rear cone without a belt, consists of a stamped steel core (St10 steel) weighing 1.43 g; lead jacket and bimetallic (steel clad with tombak) shell. The lead jacket does not reach the end of the shell, and in the front of the bullet, between the inner surface of the head of the shell and the lead jacket, there is a 5 mm long cavity, which helps to shift the center of gravity of the bullet somewhat back, which reduces the stability of the bullet when it meets the target. The edges of the shell in the tail of the bullet are rolled up with support on the bottom of the core. The bullet is not painted. In all combat cartridges of 5.45 mm caliber, except for cartridges with PP bullets, red varnish is used to seal the junction of the bullet with the edge of the case muzzle and the joint of the primer, which does not have a distinctive color. Currently out of print.
5.45 mm automatic cartridge mod. 1974 with a bullet of increased penetration PP (index 7 H10)
In 1992, a new modification of the 5.45-mm automatic cartridge model was adopted. 1974 with a bullet of increased penetration PP, developed by a creative group of designers and technologists from the Barnaul Machine Tool Plant. The bullet with increased penetration PP received a stamped elongated steel heat-strengthened core of greater mass. The core, made of St70 steel (weighing 1.72 g) or St75 (weighing 1.8 g), has a head part of a more streamlined ogive shape, a flat top with a diameter of 1.8 mm and a recess in the center of the bottom (unlike the PS bullet) . The PP bullet with increased penetration ensured penetration of alloy plates at a distance of 100 meters - 100 percent and steel plates 14 mm thick at a distance of 100 meters - at least 80 percent.
5.45 mm machine gun cartridges mod. 1974 are sealed in standard wooden cartridge boxes of 2160 pieces each. Each box holds two metal roll-up boxes containing 1,080 rounds of ammunition. There is also a packaging option in which packs of cartridges are placed not in steel boxes, but in waterproof paper bags (120 rounds each), four packs of 30 rounds each. At the same time, the inscription “moisture-proof bags” is written on the wooden box. The closure contains special abbreviated alphanumeric designations. Boxes and crates containing cartridges with special bullets are additionally marked with a colored stripe corresponding to the distinctive color of the cartridge.
Automatic cartridge 5.45x39
The article presents an automatic 5.45 mm cartridge of 5.45x39 caliber:
- Cartridge with a bullet with a steel core Ps.
- Cartridge with a bullet of increased penetration PP.
- Cartridge with armor-piercing bullet BP.
- Cartridge with armor-piercing bullet BS.
- Cartridge with T tracer bullet.
- A cartridge with a bullet with reduced ricocheting ability PRS.
- Blank cartridge with a plastic simulator bullet.
- Modernized blank cartridge.
- Training cartridge.
- Cartridge with a lead core for sporting and hunting weapons.
The history of the creation of the domestic 5.45 mm machine gun cartridge began in the late 1950s, when before the leadership Soviet Union information reached about the active development of a similar rifle complex in the USA in 1957 and later adopted assault rifle AR-15 chambered for its own small-caliber cartridge 5.56x45 mm (M193). Immediately, on the instructions of the GAU, NII-61, within the framework of the “Lightness” research project, began its own work on the creation of a similar rifle complex. Initially, according to research work, the cartridge caliber was chosen in the range of 4.5 mm, 5.6 mm, 6.5 mm, but studies have shown that the most optimal in many respects is a cartridge with a 5.6 mm caliber bullet.
Conducted extensive experiments have shown that for the ratio of recoil impulse, bullet weight, flatness of trajectory and ballistic coefficient of the bullet, it is necessary to choose a caliber from 5.0 to 5.7 mm.
As a result, 5.45 mm was chosen as the smallest bullet caliber that allowed placing a steel core in its shell and at the same time ensuring high penetration qualities and flatness of the trajectory.
As a result, at the base of TsNIITOCHMASH, Klimovsk in the early 1970s, its own automatic cartridge was “born”. . The final version of the cartridge was adopted in 1974 under the designation 7N6 and had a varnished steel sleeve in its design, the capsule socket had two seed holes with an anvil and a Berdan-type capsule of the KV-16 brand with a diameter of 5.06 mm. The bullet is 25.5mm long and weighs 3.42g. had a steel blunt-pointed core made of ST10 steel, in the bow part in front of the core there was a technological cavity. Until 1978, 5.45 mm bullets were made by bending the edges of the shell inward. In order to optimize and reduce labor intensity in the production of bullets with a steel core, it was proposed to produce bullets without subsequent bending of the shell. After research, it was concluded that this method does not in any way affect the characteristics of the bullet at the moment of firing, as a result of which, starting in 1978, factories began to produce bullets without bending the shell.
5.45 mm bullets of the 5.45x39 7N6 cartridge with a steel core:
1. Bullet produced before 1978 with a curved shell edge.
2. Bullet produced after 1978 with straight edges
In addition to the 7N6 cartridge with a steel core, a cartridge with a 7T3 tracer bullet with a length of 26.85 mm was tested in parallel. But when firing cartridges with tracer bullets, unsatisfactory accuracy was revealed. After a series of studies of factors that could influence the accuracy of fire, we came to the conclusion that the accuracy is influenced by a design feature, namely the length of the leading part of the bullet. Further research has shown that reducing the initial length by 1.5 mm significantly improves accuracy performance associated with the 7N6 cartridge. Thus, in 1976, cartridges were produced with bullets that were shortened by 1.5 mm and their length was 25.35 mm. 
Cartridge with PS bullet.
Index GRAU 7N6, 7N6M.
-Cartridge weight - 10.2-10.4g.
-Grade of gunpowder - Sf033fl.
-Bullet weight - 3.40-3.42 g.
-Bullet length - 25.50-25.65mm.
clad with tombak.
- Bullet core material - tool steel ST10, ST65G, ST70, ST75.
-The mass of the bullet core is 1.42-1.45g. 
Cartridge with increased penetration bullet PP
.
In the 90s, the main direction in the development and modernization of existing ammunition was to increase the penetration power of bullets by changing their design. In addition to the development of rifle cartridges with bullets of increased penetration, 5.45-mm machine gun cartridges with bullets of increased penetration were also developed. So, in a major experimental design work under the symbol “Castle”, both rifle and machine gun cartridges with bullets of increased penetration were tested in parallel. The development of the 5.45 mm PP bullet was carried out at the Barnaul Machine Tool Plant. The design is based on increasing the length of the steel core, which tapered towards the nose of the bullet; the mass of the bullet itself also increased due to the longer core, as well as filling the free space in the nose of the bullet with lead. This design feature of the bullet made it possible to increase its penetration capabilities to 1.5-2 times higher than that of a cartridge with a 7N6 bullet. A new cartridge with a bullet of increased penetration received the index 7N10 and was adopted by the army in 1995.
The length of the cartridge is 56.6-57.0 mm.
-Cartridge weight - 10.55-10.64 g.
-Type of gunpowder - smokeless, pyroxylin
-Grade of gunpowder - Sf033fl.
-Weight of the powder charge - 1.49-1.51 g.
-Bullet weight - 3.56-3.62g.
-Bullet length - 25.50-25.65 g.
-Bullet shell material - steel,
clad with tombak.
-Bullet core material -
tool steel, ST70, ST75.
-The mass of the bullet core is 1.72-1.80g.
-Initial bullet speed - 900-960m/s.
Pack of 30 pcs. cartridges with a bullet of increased penetration 
In addition to the development of bullets for the 5.45-mm machine gun cartridge using the method of lengthening the shape of the core and methods for processing it, it was also proposed to change the shape of the head part of the steel core due to its sharpening by analogy with armor-piercing bullets of rifle cartridges, as well as its heat treatment, which made it possible to achieve its high strength. These core processing methods made it possible to further increase the penetration ability of bullets, as a result in 1998
year, the cartridge was put into service under the designation 7N22, and its production
started at the Barnaul Cartridge Plant No. 17 in 2002. Research into options for increasing the penetrating properties of bullets of the 5.45x39 cartridge continued, so in 1998, on the basis of TsNIITOCHMASH, with the participation of the Amur plant "Vympel", a cartridge with a bullet with a metal-ceramic core was developed. By changing the shape of the bullet and its weight with the presence of a special core in its design, the designers achieved a significant increase in penetration ability in comparison with PP and BP bullets. With regard to the cartridge with a 7N6 steel core bullet, it was possible to increase penetration by 7.5 times. The cartridge was adopted for service in 2002 under the name “5.45-mm cartridge with an armor-piercing core BS”, index 7N24.
Cartridge with armor-piercing bullet
GRAU index 7N22.
Marking - the tip of the bullet is painted black.
-Chuck length - 56.6-57.0mm.
-Cartridge weight - 10.60-10.72 g.
-Type of gunpowder - smokeless, pyroxylin.
-Grade of gunpowder - Sf033fl.
-Weight of the powder charge - 1.43-1.45g.
-Bullet weight - 3.65-3.69 g.
-Bullet length - 25.50-25.65mm.
-Bullet shell material - steel,
clad with tombak.
-Bullet core material -
tool steel U12A.
-The mass of the bullet core is 1.75-1.80g.
-Initial bullet speed - 870-910m/s.
Cartridge with BS bullet
-Chuck length - 56.6-57.0mm.
-Cartridge weight - 11.3 g.
-Type of gunpowder - smokeless, pyroxylin.
-Grade of gunpowder - Sf033fl.
-Weight of the powder charge - 1.43-1.45g.
-Bullet weight - 4.1 g.
-Bullet length - 24.50-24.65mm.
-Bullet shell material - steel,
clad with tombak.
- Bullet core material - VK8.
- Bullet core mass - 2.10 g.
-Initial bullet speed - 850 m/s.
Cartridge with tracer bullet T
Index GRAU 7T3, 7T3M.
Marking - the tip of the bullet is painted green.
-Chuck length - 56.6-57.0mm.
-Cartridge weight - 10.23-10.30g.
-Type of gunpowder - smokeless, pyroxylin.
-Grade of gunpowder - Sf033fl.
-The mass of the powder charge is 1.3-1.4g.
-Bullet weight - 3.20-3.23 g.
-Bullet length - 25.0-25.2mm.
-Bullet shell material - steel,
clad with tombak.
-Bullet core material - lead
with an admixture of antimony 1-2%.
-The mass of the bullet core is 1.33-1.35g.
-Initial bullet speed - 870-910m/s.
The first serial tracer bullets (7T3) had an elongated back, and them
the total length was 26.45 mm and weight 3.36 g, and their production was carried out
until 1976. Starting in 1976, the bullets were modernized (7T3M) and had
shortened rear part, their total length was 25.32 mm and weight 3.2 g.
This decision was due to the rapid wear of the barrel when firing this
type of cartridge, as well as with unsatisfactory accuracy compared to
7N6 cartridges.
Pack of 30 pcs. cartridges with a tracer bullet with color marking in the form of a green stripe on
one side of the package.
Cartridge with reduced ricochet ability (RPS)
PRS cartridges began to be produced in the mid-90s by the Amur Cartridge Plant; the bullet in the first releases of the PRS cartridge was significantly different in its design and was a bullet with a steel core modeled on the 7n6 cartridge, where the bullet shell in the nose had a cut to the technological cavity in front of the core . There were longitudinal cuts on the inside of the shell in the nose. Since the 2000s, cartridges produced at the Barnaul Cartridge Plant had a sealant varnish at the junction of the bullet and the cartridge case, as well as on the purple capsule. On
The bottom of the cartridge case was marked in the form of a commercial mark of the factory and the caliber of the cartridge.
Further, starting from 2008, the designation of the plant number, year of production and type of cartridge “PRS” was applied to the bottom of the cartridge. Early releases of cartridges were filled with 5.45 VUfl gunpowder, and later brands Sf033fl.
Blank cartridge with plastic bullet simulator
GRAU index 7X3.
-Cartridge length - 56.0-56.3mm.
-Cartridge weight - 6.4-6.6 g.
-Type of gunpowder - smokeless, pyroxylin.
-Grade of gunpowder - Sf033fl, P-45.
-The mass of the powder charge is 0.60-0.61g.
-Bullet weight - 0.24-0.25g.
-Bullet length - 21.2-21.6mm.
-The bullet material is polymer.
Pack of blank cartridges 5.45*39 with plastic bullet
Modernized blank cartridge
Index GRAU 7Х3М.
Training cartridge
The training cartridge is intended for training in loading and unloading weapons, as well as checking the operation of mechanisms. The cartridge case is equipped with a standard bullet with a steel core. Distinctive feature for these cartridges from combat ones - the presence of recesses on the case body, located symmetrically on four sides.
Commercial version of the 5.45x39 cartridge for sporting and hunting weapons
The commercial version of the cartridge for sporting and hunting weapons is produced at the Barnaul Cartridge Plant and has a lead core in its bullet design; there is a technological cavity in the bullet nose. The commercial mark of the factory and the caliber of the cartridge are applied to the bottom of the cartridge case.
Experimental belts for the 5.45mm PU machine gun (PU-21), project “POPLIN”
In the early 1970s. TsNIITOCHMASH begins the development of a 5.45 mm machine gun with a unified supply of ammunition, which consisted of the use of both belt feed and magazine feed. Work continued until 1977, but was not completed due to unsatisfactory field tests, as well as the complex design of the machine gun
Options for one-piece belts with a capacity of 200 rounds of 5.45x39 caliber
The final version of the tape for the experimental unified 5.45 mm PU-21 machine gun
The publication uses excerpts from foreign publications.
There are different versions regarding the 5.45-mm rifle system adopted by us in 1974. The most common is that the 5.45 mm bullet is designed with a shifted center of gravity and, thanks to this, not only tumbles into the obstacle, but also breaks up into small fragments, which entails a guaranteed defeat regardless of the location of impact. In contrast to this, an opinion was expressed about the weakness of the cartridge and the inadequacy of its penetrating effect. What is the truth?
Interesting are the assessments of the 5.45 mm cartridge that appeared in the foreign press after the AK-74 assault rifle arrived in Afghanistan. The first of them were of a “sensational” nature. In particular, it was reported: “For some time now, Soviet troops stationed in Afghanistan have been using bullets of an unknown type. After penetration, a bluish color emerges from the body gaseous substance. The wounds caused by these bullets are difficult to heal.” Or: “The Russians created a 5.45 mm cartridge with a poisonous bullet, since arsenic was found in large quantities in its lead.” After some time, a more sober assessment of experts appeared: “The arsenic content in Russian 5.45 mm bullets is insignificant and they cannot be considered poisonous. Obviously, this is a consequence of the use of lead from natural deposits with arsenic impurities.”
The final opinion was as follows:
“Unlike the cartridge used in the West (M193), the Soviet one has all the properties necessary for firing from automatic weapons:
the steel sleeve has a precisely calculated groove for the extractor and a thick flange, which ensures its flawless functioning;
compared to the cartridge arr. 1943. The 5.45 mm cartridge provides better accuracy of fire, has one-third less mass, 40% less recoil impulse, less sensitivity to side winds and greater penetration;
reducing the caliber of the cartridge and using a small amount of lead in the bullet will lead to significant savings. This is especially important, since in the USSR over the past 10 years prices for lead and copper have increased significantly.”
“The USSR dared to adopt a cartridge with intra-ballistic indicators that are 10% lower than those of the M193 (in terms of pressure). However, the design of the bullet makes a very favorable impression in terms of external ballistics. There is no doubt that the Soviet Army adopted a successful cartridge that can withstand competition.”
“The Soviet AK-74 assault rifle provides 2-2.5 times greater effective firing range than the AK-47 and AKM. The 5.45 mm caliber cartridge provides 100% damage to a tall figure at 330 m and 50% at 550 m. Its bullet pierces ten rows of 19 mm pine boards, a bullet from a 7.62 mm cartridge mod. 1 943 – seventeen boards. The propellant in the 5.45mm cartridge is high-energy, with a near-perfect burn rate. It is better than American gunpowder - WC 844 from OІіп: in the M193 cartridge, Russian gunpowder of the same weight provided an initial speed of 1040 m/s instead of 995 m/s at a lower pressure of 2.5%."
“The unique design of the 5.45 mm bullet lies in the presence of a cavity in its head. The assumption that this cavity would cause deformation of the bullet and a fragmentation effect upon impact was not confirmed. It serves to shift the bullet's center of gravity toward the base and likely contributes to very early loss of stability. On average, a 5.45 mm bullet begins to turn at a depth of 7 cm, but does not break, and a bullet from the M193 cartridge begins to turn at a depth of 12 cm. However, when the bullet from the M193 cartridge begins to “yaw”, it breaks down, forming elongated fragments due to fracture along the groove on the bullet casing and subsequent destruction of the tail of the bullet (the 5.45 mm cartridge does not have such a groove). This leads to extensive wounds, reports of which began to appear with the introduction of the M16 rifle in the Vietnam War. The M855 bullet, which replaced the M193 bullet in the US Army (in 1982 when standardizing the 5.56 x 45 mm cartridge in NATO) and which is based on the SS109 bullet, also produces fragments when fired at ranges of 3, 5 and 100 m. .
5.45 mm cartridges (from left to right): with tracer bullet; with a bullet with a steel core; idle.
7.62 mm cartridges (from left to right): with reduced bullet velocity (SB); with an incendiary bullet; with a T-45 tracer bullet; with an armor-piercing incendiary bullet; with a bullet with a steel core; idle.
“The 5.45-mm AK-74 bullet loses stability in the fabric after traveling 7 cm, but does not collapse. From bullets of the M193 cartridge, the wound cavity is larger, since when fired at 3 m, after traveling 12 cm, they turn 90 degrees, are strongly flattened and broken along the annular groove into which the cartridge case neck is pressed. The head part of the M193 remains intact, and its tail section, making up approximately 40% of the bullet’s mass, breaks into many fragments that penetrate to a depth of 7 cm from the channel.”
At the same time, comparative assessments of American, German and Swedish-made NATO cartridges were carried out in the foreign press. In particular, it was reported that “a 7.62-mm bullet from a NATO cartridge made in the USA (with a tombac shell 0.81 mm thick) travels normally up to 16 cm, then begins to tumble without collapsing. However, traveling a distance of 20-35 cm and turning 90 degrees, it can cause great destruction to tissues. A similar bullet of the 7.62 x 51 NATO cartridge produced in Germany (the thickness of the bimetallic shell is 0.51 cm) moves steadily for 8 cm, then turns around and breaks at the annular groove. The wound channel is similar to the M193 channel, but the size of the tissue tear is increased by 60%. For a Russian rifle cartridge, when firing at an initial speed of 850 m/s (at 3 m), the wound channel is similar to the American cartridge 7.62 x 51.
The most destructive bullet described above is the 7.62mm bullet from the West German NATO cartridge. One can assume; that the same is the bullet of the Swedish cartridge 7.62 x 51, which causes much more extensive wounds than the M193.”
Summarizing the statements of independent Western experts, we can state: bullets of domestic cartridges, including 7.62 mm rifle and machine gun calibers 5.45 and 7.62 mm mod. 1943, are not destroyed even when fired at point-blank range at a distance of 3 m. Foreign bullets of the 5.56 mm M193 cartridge, 5.56 x 45 mm NATO M109 cartridge, 7.62 x 51 mm NATO cartridge produced in Germany and Sweden are destroyed at fragments when fired at a distance of up to 100 m or even more, severely damaging tissue. A similar impact of 7.62 mm bullets is significantly greater than that of 5.56-5.45 mm bullets. Of course; in some cases, bullet destruction is also possible when firing 5.45 mm cartridges when fired at point-blank range or in the event of a bullet hit into the bone. But this is an inevitable tribute to the shot power required for a combat cartridge.
All bullets, regardless of the position of their centers of mass, begin to turn (tumble) in the tissues under the influence of environmental resistance. How quickly this happens depends on the pitch of the barrel rifling, that is, on the stability margin of the bullets. In small-caliber bullets, the damaging effect, approaching that of larger-caliber bullets, is achieved by reducing this stability margin (increasing the rifling pitch). This forced measure to compensate for the reduction in caliber is associated with the requirement to ensure the effectiveness of bullets at all ranges combat use. We also have to take into account the characteristics of similar weapons of a potential enemy.
Finally, a few words about the creators of the 5.45 mm cartridge. The cartridge is the most conservative part of small arms. Its design must be carefully worked out in all respects, taking into account the fact that it will be in service for tens of years. In the process of mass production of cartridges, a significant improvement in their characteristics is practically impossible, since this will require changes in sights and automation in existing weapons. Some modernization is possible only if old and improved cartridges are completely interchangeable. On the other hand, the level of effectiveness of small arms largely depends on the characteristics of the cartridge, since the cartridge contains recoil impulse, flatness of trajectories, and action on the target.
In this regard, large teams of specialists are working on developing the design and manufacturing technology of the cartridge and its components, and it is impossible to name one author of the cartridge. Nevertheless, in any legend there is a certain amount of truth. In our case, it lies in the fact that when creating a 5.45-mm cartridge, the head of a group of specialists at the leading enterprise - the developer of the cartridge - was a woman - Lidia Ivanovna Bulavskaya, whose work was rightfully recognized by the Motherland. state award.
It should be noted that in 1980, one of the deputies of the German Bundestag made a request to the German Minister of Defense about the excessive lethal effect and “inhumanity” of 5.45 mm bullets for the AK-74 assault rifle used in Afghanistan. To this the answer was given that the German Minister of Defense has no complaints about the Soviet 5.45 mm cartridge in this regard. In 1981, the Soviet government received a similar request from the International Red Cross and the UN. Based on the results of extensive comparative tests, these organizations were presented with data demonstrating that the lethal effect of the 5.45 mm bullets was slightly inferior to the bullets of the 5.56 mm M193 cartridge. Numerous symposiums on the damaging effects of small arms bullets have not confirmed the validity of the demands to ban the 5.56-mm M193 cartridge on the basis of its “inhumanity.”
Rifle cartridges of 7.62 mm caliber (from left to right): with an incendiary bullet; with a T-46 tracer bullet; with an armor-piercing incendiary bullet; with a bullet with a steel core; with a heavy bullet; with a light bullet; idle.
V. DVORYANINOV, candidate of technical sciences; Lieutenant Colonel S. DERYUGIN
Kalashnikov AKS-74 assault rifle with folded stock
AK-74 with a GP-25 grenade launcher. Photo (c) KardeN
Automatic carbine AK-74 (GRAU Index - 6P20) 5.45 mm caliber, developed in 1970 by designer M.T. Kalashnikov, was adopted armed forces USSR in 1974. Is further development AKM.
In the 1970s, following the NATO countries, the USSR followed the path of transferring small arms to low-impulse cartridges with reduced-caliber bullets to lighten the wearable ammunition (for 8 magazines, a 5.45 mm caliber cartridge saves 1.4 kg) and reduces , was considered to have “excessive” power of the 7.62 mm cartridge. In 1974, a weapon complex chambered for 5.45×39 mm was adopted, consisting of an AK-74 and an RPK-74 light machine gun, and subsequently (1979) supplemented by the small-sized AKS-74U, created for use in a niche that Western armies were dominated by submachine guns, and in recent years by the so-called PDW.
Main differences from its predecessor
- a new cartridge of 5.45×39 mm caliber (instead of 7.62×39 mm), which has a flatter bullet trajectory, which led to an increase in the direct shot range by 100 meters, and is also lighter (weight savings of 1.4 kg when carried ammunition in 8 magazines);
- a new muzzle brake-compensator, which serves to increase combat accuracy and reduce recoil energy;
- The magazine is made of light and durable plastic.
For assault rifles produced in 1974-1986, the butt and fore-end are made of wood. Since 1986, they began to be made from black plastic. Longitudinal grooves were made on the wooden butt on both sides to lighten the overall weight of the machine gun. They continue to be made on plastic stocks.
Can be used with the GP-25 or GP-30 or GP-34 underbarrel grenade launcher.
The accuracy of automatic fire has improved by almost 2 times compared to the AKM (in linear dimensions). The accuracy of a single fire is approximately 50%.
The effective firing range of the AK 74 is:
For single ground and air targets - 500 meters;
For ground group targets - 1000 meters.
Direct shot range:
- According to the chest figure - 440 meters;
- In terms of height, he is 625 meters.
Normal combat requirements for AK74
- all four holes fit into a circle with a diameter of 15 cm at a distance of 100 m.
- the average point of impact deviates from the control point by no more than 5 cm in any direction.
Testing of combat is carried out by single shooting at a test target or a black rectangle 35 cm high and 25 cm wide, mounted on a white shield 1 m high and 0.5 m wide. Firing range - 100 m, position - lying down, without a bayonet, cartridges - with an ordinary bullet, scope - 3.
In general, one can note a significant improvement in the accuracy of fire compared to the AKM and especially the AK. As an example, consider the total median deviation at a distance of 800 m (vertical and width, respectively):
AK - 76 and 89 cm.
SKS - 47 and 34 cm.
AKM - 64 and 90 cm.
AK-74 - 48 and 64 cm.
Variants of the Kalashnikov assault rifle
AK-74 is the main option.
AKS-74 (GRAU Index - 6P21) - a variant of the AK74 with a triangular metal butt folding to the side. Designed for use in airborne troops(an assault rifle with a non-folding stock cannot be conveniently and safely placed in the parachute harness).
AK-74N is a “night” version of the AK-74 with a side rail for attaching night sights.
AKS-74N is a “night” version of the folding AKS-74, with a side rail for attaching night sights.
AK-74M - AK74 modernized.
Ammo used
- 7N6 (1974, bullet with a steel core, lead jacket and bimetallic jacket).
- 7N10 (1992, bullet with increased penetration, with a heat-strengthened core). Armor penetration - 16 mm from a distance of 100 m.
- 7U1 (subsonic bullet for silent shooting).
- 7N22 (1998, armor-piercing bullet with a core made of high-carbon steel U12A by cutting with subsequent grinding of the ogival part). Armor penetration - 5 mm from a distance of 250 m (2P grade), 1.9 times better than 7N6.
- 7N24 (increased manufacturing precision, heat-strengthened tungsten carbide core)
A bullet with a steel core of a 5.45 mm cartridge when fired from an AK74 provides the following penetrating effect [source not specified 1165 days]:
Penetration with a probability of 50% of steel sheets of thickness:
- 2 mm at a distance of 950 m;
- 3 mm at a distance of 670 m;
- 5 mm at a distance of 350 m.
Penetration with a probability of 80-90% of a steel helmet at a distance of 800 meters;
Penetration with a probability of 75-100% of body armor at a distance of 550 meters;
Penetration of 50-60 cm into a parapet made of dense compacted snow at a distance of 400 meters;
Penetration of 20-25 cm into an earthen barrier made of compacted loamy soil at a distance of 400 meters;
Penetration with a probability of 50% of a wall made of dry pine beams with a cross-section of 20x20 cm at a distance of 650 meters;
Penetration of 10-12 cm into brickwork at a distance of 100 meters.
In 1986, new bullets were developed with a heat-strengthened core of increased hardness, providing a significant increase in penetration: the new bullet pierces a steel helmet at a distance of 960 meters, and body armor with titanium plates at a distance of 200 meters.
Another improvement of the bullet in 1992 again increased armor penetration (the army body armor Zh85-T penetrates at a range of 200 m, and the heavy Zh95-K at a range of 50 m) with a constant initial speed. The new cartridge, which is 1.84 times superior in armor penetration to the 7N6, received the index 7N10. 7N10 provides penetration of 16 mm at a distance of 100 meters.
Advantages
High reliability of operation in difficult conditions. Simplicity and low cost in production. In the AK-74M version - support for the installation of modern sighting and tactical devices, which is essentially a way to modernize the machine gun, and support for double-row box magazines similar to the Steyr AUG, made of impact-resistant plastic, with side inserts made of transparent polymer, for visual control of the amount of ammunition in the magazine .
Since one of the reasons for the creation of the AK-74 was a change in the caliber of the cartridge used by the machine gun, from 7.62x39 mm to 5.45x39 mm, the weapon has less recoil and, accordingly, greater shooting accuracy and a flatter bullet trajectory.
Flaws
Compared to the American M4A1 carbine, the AK-74 has lower single-fire accuracy.
In comparison with weapons with balanced automatics AEK-971, AK-107/AK-108, AK-74, the accuracy of firing bursts from unstable positions is 1.5-2 times lower.
The AK-74 lacks the ability to quickly change the barrel, like the FN SCAR, Steyr AUG, HK 416, and Bushmaster ACR; as well as a fixed-length burst firing mode, which was later added to the “hundredth series” assault rifles AK101-2, AK102-2, AK103-2, AK104-2, AK105-2.
The remaining advantages and disadvantages are similar to those for the entire AK family.
Technical characteristics of the AK-74
- Caliber: 5.45×39
- Weapon length: 940 mm
- Barrel length: 415 mm
- Weight without cartridges: 3.3 kg.
- Rate of fire: 600 rounds/min
- Magazine capacity: 30 rounds
- Sighting range: 1000 m
Technical characteristics of AKS-74
- Caliber: 5.45×39
- Weapon length: 940/700 mm
- Barrel length: 415 mm
- Weight without cartridges: 3.4 kg.
- Rate of fire: 600 rounds/min
- Magazine capacity: 30 rounds
Assault rifles
