In the early seventies, a new low-impulse intermediate cartridge 5, 45x39 mm was created in the Soviet Union. It had some advantages over the existing 7, 62x39 mm, such as less weight, less recoil impulse, increased direct shot range, etc. It was decided to transfer the army to weapons under the new 5, 45-mm cartridge. The corresponding projects started back in the mid-sixties. According to the results of the competition in 1974, several samples of new weapons were adopted by the Soviet army, including the RPK-74 light machine gun.
In the late fifties and early sixties, Soviet gunsmiths worked on the creation of new small arms with the maximum degree of unification. The result of this approach to the creation of weapons was the adoption of the AKM assault rifle and the RPK light machine gun. These samples had a number of noticeable differences, but were based on general principles, and the same details were used in their design in the widest possible way. The priority of the unification of weapons led to the fact that the characteristics of the PKK as a whole remained at the level of a "full-fledged" RPD light machine gun, but almost did not increase. Nevertheless, the military wanted to simplify production and operation through unification, which led to the adoption of the RPK machine gun with the gradual displacement of the RPD.
For all its disadvantages, the idea of unification of the machine gun and the light machine gun was recognized as viable and expedient. For this reason, when developing weapons for a low-pulse cartridge, it was necessary to separately create two samples based on general ideas and components. About a dozen projects were submitted to the competition for the creation of weapons chambered for cartridge 5, 45x39 mm. Among other designers, M. T. Kalashnikov, who decided to continue the development of ideas that appeared in the AK project in the late forties.
The competition lasted until the end of 1973. The competition itself and the proposed projects are of great interest, however, almost all samples were eventually found unsuitable for adoption and dropped out of the competition. Based on the results of various field and military tests, tests and comparisons, the winner of the competition was a weapon complex developed by M. T. Kalashnikov. At the very beginning of 1974, the AK-74 assault rifle and the RPK-74 light machine gun unified with it were adopted.
The Kalashnikov weapon chambered for the new cartridge was a modified version of the previous systems. However, the RPK-74 machine gun project cannot be considered a simple alteration of the previous RPK. In addition to compatibility with the new cartridge, engineers had to solve a lot of various technological and structural issues. Thus, the RPK-74 should be considered a direct development of the ideas embodied in earlier designs.
Nevertheless, two machine guns developed by M. T. Kalashnikovs turned out to be very similar. The use of the existing proven ideas led to the fact that the general architecture of the RPK and RPK-74 light machine guns almost did not differ from each other. Both samples had a similar design of various units, as well as the same layout and general operating principles. Like other Kalashnikov developments, the RPK-74 machine gun used gas automation with a long piston stroke.
All units and assemblies of the RPK-74 machine gun were placed inside the receiver or attached to its outer part. The design of the box and lid has not undergone major changes in terms of design or production technology. The receiver itself was made by stamping, the necessary connections were made by welding. In the front wall of the box, a barrel and gas tube installation unit was provided. The front and middle parts of the box were given under the moving bolt, the rear - under the firing mechanism.
Access to the receiver was carried out using a removable top cover. The stamped cover stood on the stop at the front of the receiver and was secured with a latch at the rear. Like the box itself, the lid was borrowed from other designs in the family.
The RPK-74 light machine gun received a relatively long heavy barrel designed to provide high firepower and the possibility of prolonged intense fire. The barrel of the machine gun, as in the case of the PKK, had a length of 590 mm. At the same time, the relative length of the trunk has increased significantly. So, the RPK had a barrel length of 77.4 caliber, and the RPK-74 - 108, 25 caliber. This design feature had a positive effect on some of the characteristics of the weapon, primarily on the muzzle velocity.
In the middle part of the barrel, in its upper part, a gas outlet and fastening of a gas tube with a piston were provided. The machine gun had the same gas engine design as the AK-74 assault rifle. An interesting innovation of the RPK-74 project was the use of a special muzzle device. On the muzzle of the barrel there was a thread for installing a slotted flame arrester or a sleeve for using blank cartridges. The basic PKK did not have such a device. The barrel was installed without the possibility of replacement. This simplified the design, and also made it possible to provide acceptable combat characteristics.
The design of the bolt group was a further development of the RPK machine gun units and was unified with the corresponding parts of the AK-74. Due to the use of a new cartridge, the bolt group has undergone some changes. So, on the left side of the bolt carrier, a cutout appeared, designed to facilitate the design. The bolt was reduced and lightened, and there was no annular recess in its cup. The shape of the socket for the ejection of the liner provided in the shutter was also changed.
The principle of operation of the automation has remained the same. Under the action of powder gases, a piston rigidly connected to the bolt carrier actuated the bolt group, after which the spent cartridge case was removed. Under the action of the return spring, the bolt moved to the extreme forward position and, turning, locked the barrel. For locking, two lugs and grooves in the receiver liner were used.
The RPK-74 machine gun, like other Kalashnikov designs, received a hammer-type firing mechanism. On the right surface of the receiver there was a flag of the fire safety-translator of a characteristic recognizable shape. In the extreme upper position, the flag included a fuse blocking the trigger. In addition, in this position, the flag physically blocked the movement of the bolt group. In the other two positions of the flag, single and automatic fire was turned on. The design of the USM machine gun provided firing from a closed bolt, i.e. before pulling the trigger and / or displacing the firing pin, the cartridge had to be in the chamber.
When developing the RPK-74 machine gun, the ammunition supply system was rethought. The RPK machine gun was equipped with a double-row sector box magazine for 40 rounds or a drum magazine for 75. In addition, it could use standard magazines from Kalashnikov assault rifles for 30 rounds. When creating weapons for a low-impulse cartridge, it was decided to abandon the drum magazine. The main means of transporting and supplying ammunition was a sector store for 45 rounds. Also, the possibility of using automatic magazines of smaller capacity has been preserved.
The RPK-74 machine gun was equipped with a front sight mounted on a rack in the muzzle of the barrel and an open sight. The latter had markings for firing at a distance of up to 1000 m and allowed the introduction of lateral corrections.
Early RPK-74 light machine guns were equipped with fittings made of wood. The weapon received a forend with a gas tube cover, a pistol grip and a butt. Used "automatic" form of the forearm. The stock had a neck of reduced thickness, which made it possible to hold it by hand when firing with an emphasis. Over time, Soviet enterprises mastered the production of plastic components. As a result, machine guns began to be equipped not only with a store, but also with other plastic parts. Over time, all the fittings were replaced with plastic ones.
Like its predecessors, the new light machine gun received a folding bipod. They were attached to the front of the barrel, just behind the front sight mounts. In the folded position, the bipod was fastened with a latch and fixed parallel to the barrel. After uncoupling, they were automatically spread apart by means of a spring.
Almost simultaneously with the basic version of the RPK-74, its folding version of the RPKS-74 appeared. Its only difference was the use of a hinged buttstock. If necessary, the machine gunner could fold the butt by turning to the left, due to which the total length of the weapon was reduced by 215 mm, to some extent making it easier to carry.
The total length of the RPK-74 assault rifle was 1060 mm, i.e. 20 mm longer than the PKK. This difference in size was due to the use of a flame arrester. The self-weight of the machine gun was 4.7 kg, another 300 g fell on an empty magazine. The folding weapon modification was 150 g heavier than the base one. RPK-74 with a loaded magazine weighed about 5.46 kg. Thus, due to the modifications associated with the use of the new cartridge, it was possible to achieve an increase in some characteristics. The basic RPK with a sector magazine for 40 rounds weighed 5.6 kg, i.e. was heavier and had slightly less ready-to-use ammunition.
The developed design of the gas automatics with some innovations ensured the rate of fire at the level of 600 rounds per minute. The practical rate of fire, in turn, depended on the operating mode of the trigger. When firing single, this parameter did not exceed 45-50 rounds per minute, in automatic mode it reached 140-150.
The relatively long barrel provided a high muzzle velocity of a relatively light bullet - up to 960 m / s (according to other sources, no more than 900-920 m / s). Due to this, the machine gun could effectively fire at single ground targets at ranges of about 600 m or at group targets at a distance of up to 1000 m. It was also allowed to fire at air targets, but acceptable efficiency was achieved only at ranges of up to 500 m.
Due to the heavy barrel, the machine gun could fire in relatively long bursts. Nevertheless, some of the features of the automation led to the appearance of certain restrictions. So, firing from a closed bolt with intensive firing led to an increased risk of spontaneous firing due to heating of the cartridge case from the chamber. Thus, the shooter had to monitor the intensity of the fire and prevent overheating of the units.
On the basis of RPK-74 and RPKS-74 machine guns, modifications were developed with the ability to install additional sighting devices of various types. An interesting fact is that modifications with various additional letters in the designation differed only in the type of sight that came with the kit. The mounts for the sights were unified and represented a bar on the left surface of the receiver.
The light machine gun, equipped with a 1P29 optical sight, received the designation RPK-74P (RPKS-74P). The use of the NSPU, NSPUM or NSPU-3 night sight added the index "N", "H2" or "N3" to the name of the base weapon, respectively. Thus, the RPK-74 with the NSPU sight was called the RPK-74N, and the RPK-74 with the NSPUM product was called the RPKS-74N2. When installing a night sight, depending on the modification, the mass of the equipped machine gun could reach 8 kg.
Serial production of new weapons M. T. Kalashnikov Moscow State Medical University began in 1974. The order for production was received by the Molot plant in Vyatskiye Polyany, which had previously produced RPK machine guns. Machine guns of the new model were intended to replace existing weapons. RPK-74 machine guns have become a new weapon of fire support for motorized rifle troops at the squad and platoon level. Thus, over time, the new machine guns were able to almost completely supplant the weapons of the previous model. However, the old PKK did not go out of service immediately. For various reasons, Kalashnikov light machine guns of two models have been used in parallel for some time. In addition, both machine guns were actively used during the war in Afghanistan.
The war in Afghanistan was the first armed conflict in the course of which assault rifles and machine guns of the new family were actively used. Later, these weapons were used in a host of other wars. In fact, RPK-74 machine guns were used by all armies and armed formations that participated in conflicts on the territory of the former USSR. The most recent conflicts with the use of Kalashnikov weapons in '74 are the War of the Three Eights and the Ukrainian crisis. At the same time, Soviet-made machine guns and machine guns were used and are used by all parties to conflicts.
In the early nineties, the Izhevsk Machine-Building Plant and the Molot enterprise modernized the AK-74 assault rifle and the RPK-74 machine gun. Through some improvements, primarily of a technological nature, certain characteristics were increased. So, the resource of the barrel was increased: when using the 7N10 cartridge, the declared resource was 20 thousand shots. The receiver and its cover have been reinforced. The wooden fittings were finally replaced by glass-filled polyamide parts. In addition, it was decided to abandon a separate modification with a folding stock. The RPK-74 machine gun received a hinged buttstock. Also, like the AK-74M assault rifle, the updated machine gun received a bar for mounting sights, installed in the basic configuration.
After such changes, the general characteristics of the weapon remained the same, although the overall usability has improved to some extent. In addition, there was no longer the need to deploy the production of several separate modifications of the machine gun with various specific details, such as the butt joint or the rail for sights. As a result, the manufacturer was able to produce machine guns in one configuration and complete them with additional equipment in accordance with the wishes of the customer, or not install it at all.
The latest modifications of the Kalashnikov light machine gun mod. 1974 are RPK-201 and RPK-203. The 201st model is a variant of the RPK-74M for an intermediate cartridge 5, 56x45 mm NATO. RPK-203, in turn, is intended for the use of ammunition 7, 62x39 mm. It is noteworthy that the machine gun chambered for the 43rd year is a new development based on the RPK-74M, and not a development of the older RPK. This "origin" of weapons is due to technological and production reasons. RPK-201 and RPK-203 machine guns are intended for foreign customers, which determines the choice of ammunition used. Many countries use standard NATO ammunition, including the intermediate cartridge 5, 56x45 mm. In addition, a large number of armies using Soviet-designed cartridges have not yet switched to newer low-impulse intermediate cartridges, using 7.62x39 mm.
At the moment, the RPK-74 and RPK-74M light machine guns, as well as their modifications, are the main weapon of fire support for branches and platoons of motorized rifle companies in the armed forces of Russia and some other states. It is noteworthy that the list of advantages and disadvantages of this weapon almost completely coincides with the reviews to the previous domestic RPK light machine gun. The main advantage of all these samples is a high degree of unification with automatic machines. Also, a positive feature should be recognized the presence of a heavy long barrel, which increases firepower in comparison with machine guns.
At the same time, there are some characteristic disadvantages. More likely a minus than a plus is the lack of the possibility of replacing the barrel. In combination with firing from a closed bolt, this leads to the risk of spontaneous firing. In addition, the rejection of the drum magazine seriously hit the fighting qualities of the RPK-74 machine gun. Sector magazines for 45 rounds significantly limit the ability of the weapon to fire continuously and, as a result, affect firepower.
Nevertheless, light machine guns of the RPK-74 family chambered for 5, 45x39 mm remain in service and, obviously, will retain their status as the main weapon of support for the squad, at least for the next several years. The prospects for domestic light machine guns are not yet fully clear. Perhaps, in the foreseeable future, the RPK-74 machine guns will be replaced by new weapons of a similar class, but so far the army is using well-mastered weapons.
