A weapon that fires underwater. ADS - a unique machine for firing under water and on land (5 photos). The APS submachine gun is a personal weapon of a scuba diver and is designed to destroy underwater and surface targets, as well as to protect against marine predators.
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Since the late 1960s, developments have been carried out in the USSR aimed at creating effective weapons for combat swimmers. Navy. The work was carried out at the Central Research Institute of Precision Engineering (TsNIITOCHMASH) by O. P. Kravchenko and P. F. Sazonov. By the beginning of the 1970s, special ammunition for underwater firearms was theoretically and practically worked out, using elongated non-rotating bullets with hydrodynamic stabilization using a cavitation cavity generated by the movement of a bullet in water. The bullets had the form of elongated needles about 20 calibers long, with a head in the form of a truncated cone. The flat area at the head of the bullet was just responsible for creating a cavitation cavity that stabilizes the bullet while moving in the water. Initially, the 4.5 mm SPS cartridge and the SPP-1 4-barrel non-self-loading pistol for these cartridges were developed and adopted by the Soviet Navy.
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Approximately in 1975, a weapon complex was adopted by the Soviet Navy, consisting of an Underwater Special APS submachine gun, developed by designer V.V. Simonov, and 5.66 mm MPS special ammunition. The MPS cartridge was created on the basis of the standard cartridge case 7N6 5.45x39 mm, equipped with a needle-shaped bullet 120 mm long and specially sealed. Later, MPST ammunition appeared with a tracer bullet. In a submerged position at a depth of 5 meters, the MPS cartridge provides an effective firing range for scuba divers up to 30 meters, at a depth of 20 meters the effective range is reduced to 20 meters, and at 40 meters - already up to 10 meters. At the same time, it must be borne in mind that the line-of-sight range at the indicated depths without the use of special equipment does not exceed the effective firing range of the APS - that is, if the enemy is visible, he can be hit. The machine gun also allows firing in the air, however, due to the fact that the bullets do not have dynamic stabilization sufficient for a significantly less dense air environment, the accuracy of shooting turns out to be low, and the effective range in the air turns out to be significantly less than 100 meters. In addition, even taking into account the use of a gas regulator, the life of the machine when firing in the air is reduced by more than 10 times - from 2000 shots under water to only 180 shots in the air.
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A number of design solutions used in the APS machine, including an automatic gas regulator and a trigger device, are protected by USSR copyright certificates and RF patents.
Currently, the APS submachine gun is in service with special units of the Russian Navy and is produced in limited quantities at the Tula Arms Plant. APS is offered for export through Rosoboronexport, but there is no data on its deliveries abroad.
The APS machine is built on the basis of automation with a gas engine and locking by turning the shutter. The design of the gas outlet path provides for an automatic gas regulator, which ensures the operation of automation in such different environments as water and air. The operation of the gas regulator uses differences in the density of the media (water or air) to automatically release part of the powder gases when firing in air.
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The main parts and mechanisms of the APS assault rifle: 1 - a barrel with a receiver, a trigger, a pistol grip, a front sight and a retractable butt; 2 - receiver cover with the whole; 3 - bolt carrier with a gas piston; 4 - shutter; 5 - gas tube; 6 - reciprocating mainspring; 7 - retainer; 8 - shop; 9 - fuse-translator; |
Unlike the vast majority modern machines, APS fires from an open bolt. The trigger mechanism is shock-operated, provides fire both with single shots and automatic fire, is actuated by a single reciprocating - mainspring of the bolt group. The fuse translator is located on the receiver on the left, above the pistol grip. The loading handle is located on the right side of the bolt carrier. The receiver is made by stamping from sheet steel. A design feature of the APS is that it has a smooth (without rifling) barrel, since the bullets are stabilized hydrodynamically.
Sights - the simplest design, include an unregulated open rear sight on the receiver and a front sight on the gas chamber. Butt - telescopic, retractable, steel wire.
Without water, a person can live for a very short time. However, even less he can live under water. To overcome the resistance of this unsuitable environment for life, special units of combat swimmers are taught. Under water, they know how to survive, but there you also need to somehow fight. And here the problems begin: these super-soldiers are most often forced to kill each other in the old fashioned way - with melee weapons. The fact is that an ordinary bullet cannot swim: it quickly loses speed, begins to tumble. The range of a shot can reach only a few meters, or even one meter. Therefore, not many companies managed to develop full-fledged firearms for "fur seals" - real machine guns. And Russia is ahead of the rest here. Western armies are content with pistols and knives.
Submachine gun
special (APS-5)
APS-5 adopted Soviet army in 1975 and is still used by combat swimmer units. Under water, a long bullet-arrow of a special MPS or MPST cartridge of 5.66 mm caliber hits a target at a distance of 30 m with an immersion depth of 5 m. The deeper, the lower the effective firing range: 20 m at a depth of 20 m and only 10 m at 40 -meter depth. At extreme ranges, the arrow hits a scuba diver in a wetsuit with foam rubber insulation and pierces the mask's 5 mm thick plexiglass. APS was invented to fight enemy " fur seals"and for self-defense against sharks and other predatory marine fauna.
The machine can fire both single shots and bursts. If necessary, it can also be used on land, but practically only for self-defense. Firstly, the range of aimed shooting by arrows in the air is small - no more than 100 m. Secondly, the resource of the APS, designed for the aquatic environment, is consumed too quickly. All automation is designed to move in a receiver filled with water, when water reduces the speed of the bolt frame, and without water, instead of 2000 calculated shots, the strength of the parts is only enough for 180. The weight of the equipped machine is 3.4 kg.
1 The front sight of an unregulated mechanical sight.
2 Smooth stem. An ordinary bullet would travel a very short distance under water and capsize: hydrodynamics due to the density of the medium is very different from aerodynamics. Therefore, the APS does not shoot with bullets, but with steel arrows about 12 cm long. The cartridge case is typical, like that of 5.45 mm caliber ammunition, but the arrow in diameter is larger than a typical army rifle bullet - not 5.45, but 5.66 mm. There are no rifling protruding in the barrel.
3 Retractable example.
4 Enlarged trigger guard for comfortable grip of a gloved diver.
5 Special magazine for 26 rounds.
6 Due to the very long cartridge, the bolt has a very large stroke. Because of this, the fuse - the fire mode translator had to be placed not on the right side of the receiver, like with Kalashnikov assault rifles, but on the left.
7 Cartridge MPS (5.66 × 39 mm). Length 15 centimeters.
Pistol underwater
Heckler & Koch P11
The P11 pistol was developed by the German company Heckler & Koch in the 1970s. It is in service with saboteurs of the armies of Germany, Norway, Italy, France, England and the USA. The weapon has a block of five barrels, each of which has a cartridge with a needle-shaped bullet of 7.62 mm caliber and an electric igniter inserted at the factory. After that, the block is hermetically sealed with membranes and is essentially a disposable replacement cartridge. After all five bullets are used up in combat conditions, the barrel block is thrown away, in training conditions it is returned to the factory for reloading. The electric igniter is powered by a pair of 9 V batteries when the trigger is pressed. The gun weighs 1.2 kg without cartridges and is capable of hitting a target at a distance of 15 m with an immersion depth of 30 m. But in the air you can shoot at 30 m.
1 Front sight of a simple open sight.
2 A block of five equipped barrels.
3 Handle with sealed compartment for a pair of 9 V batteries.
4 Trigger seal.
5 Fuse.
6 The pin for attaching the interchangeable block of trunks.
7 Cartridge P11 (7.62 × 36 mm). Length 5.87 centimeters.
Special pistol
underwater SPP-1M
SPP-1 was developed at the Central Research Institute of Precision Engineering and in 1971 was adopted by combat swimmers of the USSR Navy. Produced at the Tula Arms Plant. The pistol shoots needle-shaped long bullets (their length is almost equal to the length of the barrels) with a caliber of 4.5 mm. In air, the lethal range is 20 m, in water at a depth of up to 5 m - 17 m, and when immersed at 40 m - 6 m.
SPP-1 has a block of four smooth barrels and fires from them one by one. The drummer is located on a rotating base and with each pull of the trigger it is cocked and rotated a quarter of a turn, approaching the next barrel. For reloading, the block of barrels leaned down on a hinge. All barrels are reloaded at once: the sleeves of four cartridges are combined into one block using a flat steel clip, which is inserted into the barrels from the breech and removed from them manually. This operation takes 5 seconds underwater. If the barrels were equipped with separate cartridges, it would take much more time.
1 A block of four smoothbore barrels.
2 The flag fuse has three positions: "fire", "fuse" and "loading". When the fuse is moved to the upper position - loading - the barrel block is unlocked, and then it can be folded down for loading.
3 Enlarged trigger guard for comfortable grip with a gloved hand.
4 Hinge for tilting the block of barrels for reloading.
5 SPS cartridge (4.5 × 39 mm). Length 14.5 centimeters.
Automatic two-medium
special (ADS)
This unique machine was created in the Tula Instrument Design Bureau (KBP) after 2005. In 2009, he passed military tests. The assault rifle is unique in that it can fire on land with standard 5.45 mm ammunition, and for firing under water it is enough to attach a magazine with special PSP cartridges of the same caliber to it. Since their sizes are typical, magazines for both types of ammunition are used standard and interchangeable - from AK-74. All earlier types of underwater weapons could be used effectively only under water, while on land they were inferior to a conventional machine gun.
An underwater armor-piercing bullet with a mass of 16 g moves in water, reducing resistance due to the cavitation cavity created around the bullet due to its cut nose. The bullet pierces body armor or the bottom of small boats. The firing range under water depends on the depth: at a depth of 5 m it is 25 m, and at a depth of 20 m it is already only 18 m. However, visibility at a depth is low, so it will not work to notice a target at long distances.
1 device silent shooting(tactical silencer) - on land. And under water, it works as a diffuser of powder gases, reducing the bubble when fired. This is important, since a huge bubble of powder gases and water vapor makes it difficult for the shooter to observe the results of the shot and aim to continue shooting, and even unmask it in shallow water - all this gaseous rubbish rises to the surface of the water.
2 Sight for underbarrel grenade launcher.
3 Front sight with the possibility of attaching a laser designator.
4 Picatinny rail - a universal bracket for mounting all kinds of sights: optical, night, thermal imaging, hydroacoustic, etc.
5 The bullpup layout reduces the length of the weapon, helping to crawl through the hatches of underwater vehicles, and reduces recoil. The latter is especially true under water, where the shooter does not always have a fulcrum.
6 Magazine for 30 rounds of caliber 5.45 × 39. On land, mass automatic cartridges of this caliber are used, and under water - special ones, with a sub-caliber bullet.
7 Safety trigger.
8 Underbarrel grenade launcher trigger.
9 40 mm grenade launcher.
10 Grenade launcher fuse.
11 Cartridge PSP (5.45 × 39 mm). Length 5.67 centimeters.
In the late 1960s, the Central Research Institute of Precision Engineering (TsNIITOCHMASH) began developing effective weapons for combat swimmers of the USSR Navy.
By the early 1970s, special ammunition for underwater firearms was developed using elongated non-rotating bullets with hydrodynamic stabilization using a cavitation cavity generated by the movement of a bullet in water. At the same time, the designers of TsNIITOCHMASH - husband and wife V.V. Simonov and E.M. Simonova, a 4-barrel non-self-loading pistol SPP-1 was developed and adopted by the Soviet Navy for a 4.5-mm special SPS cartridge, created by designers V. and E. Samoilov, O. Kravchenko, I. Kasyanov.
aps butt complex
And in 1975, a weapon complex was adopted by the Soviet Navy, consisting of an Automatic Underwater Special APS, also developed by husband and wife V.V. Simonov and E.M. Simonova, and 5.66 mm MPS special ammunition.
The APS submachine gun is designed to arm combat swimmers and is used to destroy enemy combat swimmers, their underwater transporters, watercraft under water and on land.
The APS machine is built on the basis of automation with a gas engine and locking by turning the shutter. The design of the gas outlet path provides for an automatic gas regulator that ensures the operation of automation, both under water and in air. The operation of the gas regulator uses differences in the density of the media (water or air) to automatically release part of the powder gases when firing in air. With it, you can change the amount of exhaust gases and, accordingly, the speed of movement of moving parts.
The barrel of the assault rifle is smooth, without rifling, and the bullet does not mechanically interact with the barrel, since the stabilization of the bullets is carried out hydrodynamically.
The receiver is made by stamping from sheet steel.
The trigger mechanism is of a striker type, which provides firing both single shots and automatic fire, is driven by a single reciprocating action spring of the bolt group. The fuse-translator of fire modes is located on the receiver on the left, above the pistol grip.
aps butt complex
The loading handle is located on the right side of the bolt carrier.
Sights - the simplest design, include an unregulated open rear sight on the receiver and a front sight on the gas chamber.
The machine has a telescopic buttstock made of round wire, which is retracted inside the receiver in the stowed position.
The APS is fed with ammunition from attached carob (box-shaped) magazines with a capacity of 26 rounds, which have a special design that excludes the cartridges from being skewed by the bullet upwards when feeding or double feeding of cartridges into the barrel. unusual shape The magazine is explained by the fact that the feeder spring, in comparison with the cartridges, has a shorter length.
A cut-off is placed in the receiver, which prevents the simultaneous filing of several cartridges into the chamber.
APS with used ammunition
The MPS cartridge used in the APS assault rifle was created on the basis of the cartridge case of the Soviet regular cartridge 7N6 5.45x39 mm. The unusual caliber - 5.66 mm - has a fairly simple explanation. The ammunition of the machine gun was created using a standard steel sleeve of a 5.45-mm Soviet machine gun cartridge. 5.45 mm - caliber of rifled barrels in the fields. The diameter of 5.45 mm barrels along the rifling is 5.66 mm, the same nominal diameter the leading part of the bullets of 5.45-mm automatic cartridges. The diameter of the steel bullet of the APS assault rifle corresponds to the outer diameter of the cartridge bullet of 5.45x39 mm. But since the MPS bullet does not cut into the rifling, the APS barrel caliber corresponds to the outer diameter of the bullet and has the corresponding designation - 5.66 mm.
Cartridge 5.66x39 mm MPS
Caliber, mm 5.66x39
Length, mm
- stock unfolded 823
- stock folded 615
Weight without magazine, kg 2.46
Shop, kol. rounds 26
Rate of fire, rds / min 500 - 600
The bullet of the MPS cartridge is a steel rod with a narrowing of the head part in the form of a double truncated cone. Bullet length - 120 mm, weight - 20.3-20.8 g. Initial bullet speed in air - 365 m / s. The initial speed of a bullet at a depth of 5 m is 240-250 m / s. Chuck length - 150 mm. Cartridge weight - 27-28 g. MPS cartridges have a relatively high accuracy of fire, are protected from corrosion in sea water and penetration of water into the powder charge and primer-igniter. The cartridge case is of a traditional design, it contains a propellant powder charge that ejects a bullet from the barrel and activates the weapon's automation, based on the use of the energy of gases discharged from a hole in the barrel wall. Bullet stabilization in water is carried out due to the formation of a cavitation cavity around the bullet during movement. The formation and retention of the cavitation cavity is ensured by the appropriate selection of the shape and size of the bullet and its speed. The barrel of the APS assault rifle is smooth, without rifling, and the bullet does not mechanically interact with the barrel. The bullet does not stabilize in air.
The striking ability of the MPS cartridge bullet depends on the depth of immersion. At depths of up to 5 m, the lethal range is 30 m. At a depth of 40 m, it drops to 10 m. In all cases, the lethal range under water exceeds the target’s visibility range - that is, if the enemy is visible, he can be hit. At a distance of more than 15 m, accuracy when firing from the APS is noticeably reduced. And, probably, this circumstance, combined with the often poor visibility under water, led to the need to include an MPST cartridge with a tracer bullet in the ammunition load, which allows you to adjust the shooting along the tracks.
The lethal force of the APS at extreme distances under water strikes the enemy dressed in a "dry" wetsuit with foam padding, and also breaks through plexiglass up to 5 mm thick.
APS when used underwater
On land, the flight of a bullet - needles do not stabilize, but at a distance of 30 meters all hits fit into a circle with a diameter of 15 centimeters, the lethal force of a bullet - needles on land is maintained at a distance of up to 100 meters, but the dispersion of hits is already such that there can be no aimed shooting and speech. In addition, even taking into account the use of a gas regulator, the life of the machine when firing in the air is reduced by more than 10 times - from 2000 shots under water to only 180 shots in the air.
Underwater rifle machine APS is a unique development, which laid the foundation for the development of a new (aquatic) environment for the use of self-cocking firearms and automatic weapons in it.
The production of APS in limited quantities was established at the Tula Arms Plant, and was even offered for export through RosOboronExport.
In the 1950s, the first scuba gear was created. This gave people the opportunity to use the underwater environment as an arena for military operations. Since ancient times, divers have used knives as a means of self-defense. However, knives in underwater combat are ineffective. The chances of a swimmer armed with only one blade to survive were minimal. The use of harpoon guns turned out to be impractical: they had a weak lethal force and a low rate of fire. They could only be used for spearfishing or as protection against sharks. The successful repulsion of an attack by a specially trained enemy under water became possible with the use of underwater firearms.
Work on its creation was carried out by designers in many countries. One of the samples that subsequently gained popularity was the APS underwater shooting machine. Information about what this weapon is and what similar models used by combat swimmers of other states, is contained in the article.
Getting to know the machine
APS (special underwater submachine gun) is an individual weapon of a scuba diver used to destroy surface and underwater targets. In the mid-1970s, the weapon entered service with the Soviet Navy.
Beginning of work
In 1955, the USSR was shaken by terrible news: as a result of a catastrophe that occurred on the territory of the Sevastopol Bay in Novorossiysk, a battleship sank. Soviet specialists were convinced that this happened as a result of a sabotage successfully carried out by the enemy. Despite the fact that the results of the investigation did not provide any basis for allegations of external interference, the tragedy that occurred led the Soviet military to think about how to successfully defend against real underwater attacks by sabotage groups. Soon in the USSR special combat units, whose swimmers were armed with APS underwater assault rifles created by Soviet designers (a photo of the weapon is presented in the article).
About developers
Research and development work was carried out by a group of employees of the TsNIITochmash enterprise in the city of Podolsk. V.V. was appointed its leader. Simonov. Cartridges for weapons were developed by P.F. Sazonov and O.P. Kravchenko. The first version of the APS submachine gun was assembled by the Soviet designer P. A. Tkanev. In 1975, mass production was launched at the arms factory in the city of Tula. this weapon. Underwater submachine gun special (APS) was intended for special forces soldiers of the air fleet Soviet Union. Today, these weapons are used by Russian and Ukrainian combat swimmers.
What problem did the designers face?
Designing the underwater weapon, the designers found that it could fail quite easily. The reason for the breakdowns was the high resistance of water, which contributes to the accumulation of steam in the trunks. This factor had to be taken into account in the work on the APS submachine gun.
Developments
Shooting from the APS underwater assault rifle is carried out using the MPS ammunition (special marine cartridge) of 5.6 mm caliber developed for it. The cartridge is equipped with a needle-shaped arrow-shaped bullet with constrictions in the head. Bullet length - 120 mm. Its weight is 15 g. The stability of movement in water and the conservation of energy when firing at long distances became possible due to a special cavitation cavity, with which the developers equipped the bullet in the head. Shooting correction is carried out using special tracer marine cartridges (MPST). Since rifling is not provided for the barrels of APS submachine guns, the bullet does not receive the torque necessary for its stable movement. As a result, a projectile fired from the APS is capable of hitting a target at a distance not exceeding one hundred meters. This significantly limits combat capabilities scuba diver on dry land. For combat swimmers, Soviet designers additionally designed SPP-1 (special underwater pistols), which are also adapted for firing under water. As ammunition for SPP-1, cartridges of MSP and MPST were intended.
How is the weapon made?
The steel box of the machine is made of stamped steel sheet. Despite the fact that the APS is designed for firing under water, outwardly it is very similar to the land model. For underwater weapons, a special mechanism has been developed that automatic recharge. In his work, the energy of powder gases removed from the bore is used. The trigger mechanism allows the fighter to fire single shots and bursts. The firing mode is regulated by a special translator. It is located on the receiver on the left side. The machine is equipped with a retractable metal wire butt, which is easily extended from the receiver. In the conditions of the campaign, the butt is pushed back into the receiver, and the machine itself is attached to the side of the underwater vehicle.
Operating principle
During the shot, the shutter of the machine gun moves back. As a result, the barrel channel opens, the spent cartridge case is removed and extracted from the chamber. The bolt carrier acts on the return spring. The result of the compression of the spring was the movement of the cutter and the installation of a trigger mechanism on the cocking. Straightening, the spring with the help of the shutter sends the next ammunition into the chamber and closes the barrel channel. For the receiver, special lugs are provided. With their help, the shutter is locked. If its lugs have gone beyond the stops, then the locking procedure is considered completed. During the forward movement of the bolt frame, it interacts with the drummer, which is equipped with a striker. The shot occurs as a result of breaking the cartridge primer with this striker.
About the ammunition supply of underwater weapons
Ammunition is contained in a box-shaped double-row magazine. Its capacity is 26 rounds. The automatic magazine is equipped with a special dividing plate and spring grips, with the help of which the upper ammunition is securely fixed.
On the performance characteristics of the APS
The underwater machine has the following characteristics:
- The weapon weighs 2.46 kg.
- Length - 84 cm (with unfolded butt), 62 cm (without butt).
- Ammunition: MPS and MPST caliber 5.66 mm.
- Rate of fire: 600 rounds per minute.
- The speed of a bullet fired underwater is 360 m/s, in air: 365 m/s.
- Under water, the combat resource of the machine is 2 thousand shots, on land - 180.
- The aiming range indicator under water varies within 10-30 m, on the shore - no more than 100 meters.
In order to break through organic glass with a thickness of 0.5 cm and an enemy wetsuit, the lethal force of an APS submachine gun is enough. Analogues of this Soviet weapons are in service with the Navy in other states.
Underwater weapons for Chinese swimmers
On the basis of the Soviet APS, individual small arms were designed for combat scuba divers of the PRC. The model entered service in 2006 and is listed as QBS-6. The product is an underwater submachine gun designed to destroy underwater and surface enemy targets. Structurally, the QBS-6 has much in common with the Soviet rifle model.
The locking of the barrel in the Chinese underwater machine is carried out using a butterfly valve. The receiver is made of stamped steel sheet. The Chinese APS differs from the Soviet APS in the presence of a plastic forearm. In an effort to ensure the most convenient use of the machine, the Chinese designers equipped it with fairly wide trigger guards. The barrel channel of the weapon does not contain rifling. For the machine, the presence of shoulder wire stops is provided. The magazine capacity is 25 rounds. The caliber of the cartridges used is 5.8 mm. The underwater machine is equipped with non-adjustable fixed sights.
NATO option
An alternative to the Soviet APS for combat swimmers of NATO countries was the BUW-2 underwater weapon. This rifle model is a semi-automatic underwater pistol that fires active-reactive bullets. Ammunition BUW-2 have hydrodynamic stabilization. The place for cartridges was a special disposable block, which includes four barrels. The range of underwater shooting does not exceed 10 meters. On land, bullets hit a target at a distance of up to 250 meters. Caliber 4.5 mm. The bullet is a steel needle, the length of which can vary from 30 to 60 mm. In addition, ammunition for the NATO underwater pistol can be equipped with special ampoules with poisonous substances. Magazine capacity - no more than 20 rounds.
About the German pistol P-11
This underwater small arms was developed by the famous German company Heckler Koch. A special interchangeable block with barrels built into it is provided for the pistol. They are equipped in the factory. Rechargeable only in a specialized workshop. After shooting all the charges, the block from the pistol is dismantled. For the P-11, an electric igniter and an electronic trigger mechanism have been developed, with the participation of which the initiation of barrel electric caps is carried out. The weapon runs on two 9-volt batteries.
They are located in the handle, in a special sealed compartment. Thanks to the electronic mechanism, the P-11 is provided with an easy descent. Ammunition caliber - 7.62 mm. The cartridge is equipped with a needle-shaped bullet with a lead core. Shells in armor-piercing ammunition are painted black and contain steel cores. The effective range of underwater firing is not more than 15 meters. On land, the pistol is capable of hitting a target located at a distance of up to 30 meters.
Today, this rifle model is used by combat swimmers of such states as Germany, France, Great Britain, Norway and the USA.
Caliber: 5.6x39 mm
Automation type: gas outlet, locking by turning the shutter
Length: 823/ 615 mm (stock unfolded / folded)
barrel length: no data
The weight: 2.4kg without magazine, 3.4kg with loaded magazine
rate of fire: 600 rounds per minute (in air)
Score: 26 rounds
Since the late 1960s, developments have been carried out in the USSR aimed at creating effective weapons for combat swimmers of the Navy. The work was carried out at the Central Research Institute of Precision Engineering (TsNIITOCHMASH) by O. P. Kravchenko and P. F. Sazonov. By the early 1970s, special ammunition for underwater firearms was theoretically and practically worked out, using elongated non-rotating bullets with hydrodynamic stabilization using a cavitation cavity generated by the movement of a bullet in water. The bullets had the form of elongated needles about 20 calibers long, with a head in the form of a truncated cone. The flat area at the head of the bullet was just responsible for creating a cavitation cavity that stabilizes the bullet while moving in the water. Initially, the 4.5mm cartridge SPS and the 4-barrel non-self-loading pistol SPP-1 for these cartridges were developed and adopted by the Soviet Navy. Approximately in 1975, a set of weapons was adopted by the Soviet Navy, consisting of an Underwater Special APS submachine gun, developed by designer V.V. Simonov, and 5.66mm MPS special ammunition. The MPS cartridge was created on the basis of the standard cartridge case 7N6 5.45x39mm, equipped with a needle-shaped bullet 120 mm long and specially sealed. Later, MPST ammunition appeared with a tracer bullet. In a submerged position at a depth of 5 meters, the MPS cartridge provides an effective firing range for scuba divers up to 30 meters, at a depth of 20 meters the effective range is reduced to 20 meters, and at 40 meters - already up to 10 meters. At the same time, it must be borne in mind that the line-of-sight range at the indicated depths without the use of special equipment does not exceed the effective firing range of the APS - that is, if the enemy is visible, he can be hit. The machine gun also allows firing in the air, however, due to the fact that the bullets do not have dynamic stabilization sufficient for a significantly less dense air environment, the accuracy of shooting turns out to be low, and the effective range in the air turns out to be significantly less than 100 meters. In addition, even taking into account the use of a gas regulator, the life of the machine when firing in the air is reduced by more than 10 times - from 2,000 shots under water to only 180 shots in the air.
Currently, the APS submachine gun is in service with special units of the Russian Navy and is produced in limited quantities at the Tula Arms Plant. APS is offered for export through RosOboronExport, but there is no data on its deliveries abroad.
The APS machine is built on the basis of automation with a gas engine and locking by turning the shutter. The design of the gas outlet path provides for an automatic gas regulator, which ensures the operation of automation in such different environments as water and air. The operation of the gas regulator uses differences in the density of the media (water or air) to automatically release part of the powder gases when firing in air.
Unlike the vast majority of modern assault rifles, the APS fires from an open bolt. The trigger mechanism is striker, provides fire with both single shots and automatic fire, is driven by a single reciprocating action spring of the bolt group. The fuse translator is located on the receiver on the left, above the pistol grip. The loading handle is located on the right side of the bolt carrier. The receiver is made by stamping from sheet steel. A design feature of the APS is that it has a smooth (without rifling) barrel, since the bullets are stabilized hydrodynamically.
Sights - the simplest design, include an unregulated open rear sight on the receiver and a front sight on the gas chamber. Butt - telescopic, retractable, steel wire.
APS cartridges are fed from attached carob (box-shaped) magazines with a capacity of 26 cartridges, which have a special design that excludes the cartridges from being skewed by the bullet upwards when feeding or double feeding of cartridges into the barrel.
