As you know, in 1971 in the USSR, after three years of significant in terms of volume and tension of searches, experiments and development of various designs carried out at the Central Scientific Research Institute of Precision Engineering (TsNIITOCHMASH), an underwater pistol complex consisting of 4, 5- mm of a special underwater pistol SPP-1 and a special cartridge ATP. The next example of weapons in the system of underwater small arms, the requirements for which were formulated by the customer, was to be an underwater machine gun complex, the development of which began in 1970. However, underwater machine guns, being created in two different versions, never entered service.
BET ON SPECIALIZED
In the 1960s, the command of the USSR Navy was closely engaged in the creation and deployment of underwater reconnaissance, sabotage and anti-sabotage forces. To equip them, a wide variety of weapons and equipment were required. One of these samples was to be an underwater machine gun.
The submarine machine gun, according to the idea of the customer - the Anti-submarine Armament Directorate of the USSR Navy, - was supposed to equip ultra-small submarines (SMPL) - transporters of light divers of the "Triton" type, which at that time were also under construction.
In 1970, the technical design of the improved Triton-1M submarine was finally approved, and in 1971-1972 two prototypes of the underwater vehicle were built at the Novo-Admiralteyskiy plant in Leningrad to conduct comprehensive tests and study the features of their operation. In 1973, the Triton-1M submarine successfully passed state tests and was subsequently put into service.
The Triton-1M, an ultra-small submarine for light divers, was created to perform a wide range of tasks, including those related to patrolling the waters of ports and raids, as well as searching for and destroying underwater scouts and saboteurs. It was for the defeat of the enemy combat divers (swimmers) and their underwater means of movement that it was supposed, according to the customer's plan, to equip the Soviet ultra-small submarine with underwater machine guns.
Recall that the Triton-1M crew consisted of two people, who were in individual breathing apparatus in a cabin permeable to seawater, closed with a plexiglass fairing. It was assumed that one of the crew members was supposed to operate the underwater vehicle, and the second could fire from a machine gun installed in the bow of the underwater vehicle.
FROM THE PISTOL TO THE MACHINE
In the Soviet Union in the early 1970s, only employees of the Central Research Institute of Precision Engineering, located in Klimovsk, near Moscow, had experience in developing underwater firearms. During the development work on the creation of an underwater pistol complex (ROC "Underwater pistol", code "Moruzh"), carried out in 1968-1970, they solved the most difficult task - hitting a living target under water by shooting small arms fire.
In the course of this development work, significant prospecting studies and experimental work were carried out to determine the method of throwing the striking element, the method of stabilizing the bullet when moving in water, the parameters necessary to ensure the performance of the tactical and technical task were determined for the internal and external ballistic characteristics of the weapon and its elements, the design elements of various cartridges and the pistol itself have been worked out. Naturally, the experience of creating an underwater pistol complex was used to develop a fundamentally new type of weapon - an underwater machine gun complex.
The experimental design work "Underwater machine-gun complex", code "Moruzh-2" ("Moruzh" - naval weapon), in accordance with the decree of the Council of Ministers of the USSR and by order of the Anti-submarine weapons department of the USSR Navy, was started in 1970. TsNIITOCHMASH was appointed the lead developer of the entire complex and the cartridge, and the Tula Central Design and Research Bureau of Sports and Hunting Weapons (TsKIB SOO) was appointed the developer of the machine gun. The work was supposed to be completed with state tests in mid-1973.
It should be noted that in view of the particular urgency and importance of the task, the creation of a machine-gun complex, however, as before a pistol one, was carried out in the course of development work, bypassing any scientific research. Usually, any ROC on the creation of a weapon model should be preceded by research work (R&D) aimed at substantiating the requirements for weapons, and finding ways to solve the problem. The task of creating an underwater machine-gun complex was also complicated by the fact that first it was necessary to create a cartridge that would ensure the defeat of the target at a given range and depth, and only then the weapon for it.
The machine-gun complex had high requirements for the range and depth of use under water, exceeding those for the SPP-1 pistol. So, for example, the machine gun, according to the customer's requirements, was supposed to ensure the defeat of living targets at a depth of 40 m. At the same time, at a depth of 20 m and at a distance of up to 15 m, it was necessary to penetrate a control shield made of pine planks 25 mm thick, upholstered on the rear side with steel sheet 0.5 mm thick. It was believed that breaking through such an obstacle would ensure a reliable defeat of a combat swimmer in underwater equipment and a plexiglass fairing protected by a visor of an ultra-small submarine (a carrier of light divers). In addition, quite high requirements for the accuracy of automatic fire were imposed on the machine-gun complex. So, the radius of 50% of hits when firing at a distance of 30 m from a rigidly fixed machine gun in three series of 20 shots should not exceed 30 cm. to the arrow) about 40-50%.
SPECIAL CARTRIDGE
Based on the importance of the task, the director of TsNIITOCHMASH Viktor Maksimovich Sabelnikov took over the scientific leadership of the entire work. He appointed Pyotr Fedorovich Sazonov, the chief designer of rifle ammunition at the Institute, as his deputy.
The specifics of the new work also predetermined the fact that employees of Department No. 23 - the "cartridge" department of TsNIITOCHMASH, who had previously participated in the creation of the pistol complex, were appointed responsible for the creation of the machine-gun complex as a whole and the ammunition for it. Ivan Petrovich Kasyanov, the leading engineer of the department, who was replaced in 1972 by Oleg Petrovich Kravchenko (in 1970, the senior engineer of the department), was appointed the responsible executor of the ROC "Moruzh-2".
It should be noted that it was Kasyanov and Kravchenko who were the authors of the design of the turbine-type bullet. They subsequently received a patent for this invention. The turbine-type bullet had special grooves beveled on one side in the head part, which ensured its rotation from the action of the water resistance force. It was this type of bullet that showed the best results during the Moruzh R&D project and was put into service as a part of the 4.5-mm SPS cartridge for the SPP-1 pistol. The same type of bullet was originally supposed to be used in a promising machine gun cartridge.
Preliminary ballistic calculations carried out at the initial stage of the draft design showed that it was possible to achieve the specified tactical and technical requirements by increasing the power of the cartridge by increasing the mass of the propellant charge and using a turbine-type bullet weighing 25 g and caliber 5, 6 mm. The muzzle velocity of the bullet was supposed to be about 310 m / s. It was supposed to achieve the satisfaction of the requirements for unification and reduction of the cost of mass production by using a cartridge case from a 5, 45-mm automatic cartridge in the new cartridge, the development of which had already been completed by that time.
Under the cartridge with the above characteristics in TsKIB SOO in 1970, a preliminary design of an underwater machine gun was developed. The machine gun received the developer's code TKB-0110. Aleksandr Timofeevich Alekseev was appointed the leading designer of the machine gun. The automation of the experimental TKB-0110 machine gun worked due to the recoil of the barrel.
In the 1960s – 1970s, the USSR created the Shkval submarine missile, the high speed of which was ensured not only by a jet engine, but also by using the phenomenon of cavitation. The phenomenon of cavitation was studied by scientists at the Central Aerohydrodynamic Institute (TsAGI) in the 1960s. With the receipt in 1970 from TsAGI of information about the theory of cavitation and cavitation flow around rapidly moving elongated bodies under water, as well as the results of tests of 4.5 mm ATP cartridges at the TsAGI base in Dubna, TsNIITOCHMASH began designing a bullet with a truncated cone. The end part of the truncated cone was the cavitator. In this case, the dimensions of the cavitator (the amount of bluntness of the bullet head) were determined experimentally.
The cavitator, when the bullet moved under water at a sufficiently high speed, provided a rarefaction of water around the bullet with the formation of a cavity. The bullet moved inside the bubble without touching the side surface with water. The tail part of the bullet, striking the edges of the cavity, planed, thereby centering it in the cavity. This ensured the stable movement of the bullet in the water.
It should be noted that bullets with a truncated cone were much more technologically advanced than bullets of a turbine type, and at this stage of development they were comparable with them in accuracy and range of lethal action. Subsequently, during the development of the design, the bullets with a truncated cone provided better range and accuracy of fire than bullets of other designs.
At the stage of the preliminary design, 13 variants of cartridges with turbine-type bullets and with a truncated cone - a cavitator - were developed. Their tests at the end of 1970 at the test base of anti-submarine weapons of the Navy on Lake Issyk-Kul (Przhevalsk) made it possible to optimize the shape of the warhead and the size of the bullet for the machine-gun cartridge.
In 1971, at the technical design stage, eight variants of bullets were presented and tested, seven of them with a truncated cone (including those rotating due to the use of a rifled barrel and a leading belt on the bullet) and only one with a turbine-type bullet. Subsequently, to work out the head of a bullet with a truncated cone, five more options for bullets of various lengths, weights and designs were created and tested. As a result, the caliber of the bullet (which was 5, 65 mm), its length, mass and muzzle velocity were finally determined. The shape of the ogival part of the bullet, which has two cones, and the dimensions of the cavitator were also determined. The cartridge ensured the fulfillment of the requirements of the tactical and technical assignment for the range and accuracy of fire and the depth of use. He received the name "MPS".
Simultaneously with the search for an optimal ballistic solution and the development of the design of the bullet, the developers of the cartridge had to solve other problems - sealing the cartridge, working out protective coatings and developing a new propellant charge.
It should be noted that such a relatively long term for the creation of a cartridge for an underwater machine gun is not at all about the sluggishness of the developers of TsNIITOCHMASH, but about the extreme complexity of designing a fundamentally new cartridge, in which a number of design and technological solutions were developed and applied for the first time in the world. At the same time, the design and development of the cartridge was carried out at the stages of the preliminary and technical design of the experimental design work, and not in the course of scientific research in research work.
Moruzh-3
At the end of 1971, the developers of the machine gun finally got the opportunity to come to grips with the direct testing of weapons - the second part of the entire machine gun complex.
It should be noted here that in the early 1970s, when they began to develop an underwater machine-gun complex, there was no theory and experience in creating such automatic systems. The movement of the moving parts of automatic firearms when firing underwater has not been studied. A significant problem due to the large elongation cartridges was the creation of a reliable power supply system and, most importantly, sending the cartridge into the chamber. There was no clarity about the choice of an automation system, which was supposed to work reliably both in water and on land. Many issues in the design of a fundamentally new weapon were solved experimentally and on the inspiration of its creators and almost completely depended on the abilities of the designers.
In order to clarify the problematic issues of creating underwater automatic small arms in 1971, research work was started at TsNIITOCHMASH (R&D "Moruzh-3"). Its purpose was to conduct theoretical and exploratory research to determine the possibility of creating a manual underwater automatic firearms. In the course of the work, it was planned to develop an experimental model of a 4.5-mm underwater submachine gun chambered for the ATP. The responsible executor of this work, carried out under the leadership of the director Viktor Maksimovich Sabelnikov and the head of the research department of small arms Anatoly Arsenievich Deryagin, was appointed a design engineer of the first category of department 27 Vladimir Vasilyevich Simonov. But about the influence of this work on the fate of the machine gun - a little later.
At the end of 1971, only at the final stage of the technical project of the machine-gun complex, the developers from Tula received a batch of rounds of the Ministry of Railways for testing their machine gun. Naturally, the delay in the development of the cartridge also led to a delay in the development of the machine gun at TsKIB SOO. This could not but cause the chief executive of the ROC well-grounded fears of disrupting the deadline for the fulfillment of the state task, for the failure of which they were punished severely. As a result, the director of TSNIITOCHMASH V. M. Sabelnikov decided to urgently develop an underwater machine gun at the institute in parallel with TsKIB SOO.
The responsible executor of the work on the creation of the machine gun was appointed Pyotr Andreevich Tkachev, deputy head of the 27th department of TsNIITOCHMASH (at that time, the 27th department was the research department of the prospects for the development of small arms and melee weapons). The design group under the leadership of Tkachev included employees of the department Evgeny Yegorovich Dmitriev, Andrei Borisovich Kudryavtsev, Alexander Sergeevich Kulikov, Valentina Alexandrovna Tarasova and Mikhail Vasilyevich Chugunov. Within two months, the design group developed working design documentation for the underwater machine gun, and its drawings were transferred to the TsNIITOCHMASH pilot production facility.
By the time the P. A. Tkachev was already an experienced weapons designer. For the first time, he proposed fundamentally new schemes for the automation of hand-held automatic weapons and created several experimental models of automatic weapons with balanced automation and accumulated recoil momentum. Subsequently, these developments were used to create the SA-006 assault rifles in Kovrov and AN-94 in Izhevsk. Non-trivial abilities of P. A. Tkachev was also required when creating an underwater machine gun.
PROTOTYPE
In 1972, the light saw the light of the 5, 65-mm experimental underwater machine gun AG-026 developed by TsNIITOCHMASH chambered for the Ministry of Railways. Requirements for the small dimensions of the machine gun (and first of all for the length), which were determined by the limited volumes of the Triton-1M cabin, required the development and use of original design solutions in the weapon.
So, the work of automatics of a machine gun under a sufficiently powerful cartridge was based on the recoil of a free bolt. At the same time, the lightweight bolt was connected by gearing with two massive flywheels. This provided a large reduced mass of the recoil parts, which provided, due to a sufficient moment of inertia, the necessary delay in unlocking the bolt after a shot and at the same time a small cross-section of the moving parts of the automation, which reduced water resistance. To exclude the bounce of the shutter when it strikes in the extreme forward and rear positions, spring-loaded split rings were introduced into the flywheel design, which were put on the flywheels. When the shutter and the flywheel stopped, the rings continued to rotate and, due to friction, kept the shutter in the front or rear position, preventing it from rebound.
The cartridges were fed from a flexible metal tape with a capacity of 26 cartridges closed in a ring. The original tape, due to its design, provided not only the retention and supply of the cartridge to the ramming line, but also its direction into the barrel during the ramming process. To avoid snagging, the tape was placed in a metal box.
The movement of the tape to the ramming line was carried out by a spring, cocked by the bolt during rollback. The shot was fired from the rear sear. The sending of the cartridge into the chamber was carried out by a bolt, by direct feeding from the link of the tape located on the axis of the barrel bore. Shooting casings were inserted into the link of the tape. In case of a misfire, the machine gun was reloaded manually by rotating the flywheels. The truncated cartridge was then inserted into the tape.
The capsule was broken by a drummer fixed on the shutter mirror. To prevent premature pricking of the primer when the cartridge was discharged, an ejector was located between the shutter mirror and the bottom of the sleeve, which was removed from the gap 1.5 mm before the shutter came to the front position.
For installation on underwater carriers, a trunnion was attached to the barrel of the machine gun, with the help of which the machine gun was fixed above the instrument panel in the Triton's cockpit. A version of a machine gun with a front grip under the barrel was also developed - a kind of version of a light machine gun. This machine gun could be fired by holding it with both hands.
The applied design solutions made it possible to create a machine gun with a length of only 585 mm and a mass of less than 5 kg.
As mentioned above, simultaneously with the development of the underwater machine gun, research began on the creation of an underwater submachine gun for the ATP pistol cartridge. By the end of 1971, Simonov had created an experimental prototype of a 4.5 mm M3 submarine submachine gun. This weapon was tested by automatic firing in the hydraulic tank. The submachine gun showed satisfactory accuracy. Based on the results of the firing, it was decided to further develop manual automatic weapons under the 5, 65-mm round of the Ministry of Railways. With the consent of the customer, they decided to use these cartridges in an individual automatic underwater weapon.
By the beginning of 1972, Simonov had created an experimental 5, 65-mm underwater submachine gun AG-022. A number of field experiments were carried out with this sample within the framework of the Moruzh-3 research project. The studies were carried out in a hydraulic tank and at a test base on Lake Issyk-Kul. They showed the fundamental possibility of creating an individual underwater automatic weapon for the 5, 65-mm cartridge of the Ministry of Railways.
It is worth noting here that due to the use of the same cartridge with almost the same length of the barrel of the weapon, the machine gun and the machine gun turned out to be close in fire power.
In 1973, underwater machine guns TsKIB SOO and TsNIITOCHMASH passed factory tests and were presented for state tests. Tests showed that both machine guns - both TKB-0110 and AG-026 - did not fully meet the requirements of the tactical and technical assignment, it was necessary to refine their design.
In view of the circumstances, jointly the customer and the chief executor of the ROC, it was decided to continue work on the creation, but already within the framework of the Moruzh-2 ROC extended for 1973-1974, only an assault rifle chambered for the Ministry of Railways. Their result was a change in the designation of the caliber of weapons by 5, 66 mm, the creation and adoption in 1975 of a 5, 66-mm machine gun of an underwater special APS with an MPS cartridge, refinement of the design of the main cartridge bullet, the creation of an MPST cartridge with a tracer bullet.
Other work was carried out on underwater weapons, but they no longer had any relation to the underwater machine gun, its story ended in 1973.
