Now you can't hide under water
Until now, there has been no universal solution to the problem of using small arms ammunition in water and air. If we take the domestic APS assault rifle (special underwater assault rifle), then with all its indisputable advantages, it is not in the best way adapted to shooting in the air. Also, a special machine gun is not particularly effective when firing in the direction of "air-water surface".
Long spoke bullets do not maintain their direction of travel when hitting water, and sometimes even collapse. On large munitions, the problem is solved by creating a cavitation bubble from water vapor, which significantly reduces the resistance to movement in the water column. The most famous serial embodiment of this idea was the VA-111 Shkval torpedo missile, which is set in motion by a jet engine. Of course, there is a lot of noise from such a device, but the ammunition moves under water very quickly - more than 300 km / h (on average, 6 times faster than a conventional torpedo), which seriously complicates the enemy's response. By the way, the very effect of cavitation initially brought engineers only a headache. Cavitation cavities formed during operation on ships' propellers forced the developers to create complex shapes of the blade surfaces that are maximally resistant to the harmful phenomenon. For warships and submarines, cavitation creates another problem - excessive unmasking the noise of the propellers. A side effect of studying the hydrodynamics of cavitation was the discovery of the "vapor bubble" effect, which significantly reduces the resistance to movement in water.
In the Norwegian office of DSG Technology, they have developed special bullets that are not afraid of meeting with a water obstacle, or generally capable of working only in the water column. To implement the idea, firstly, a high specific gravity of the bullet was required - they coped with this with the help of a tungsten carbide core, which, of course, seriously increased the cost of each shot. Secondly, the special shape of the bullet nose allows creating a vapor bubble in a liquid medium denser than air, which reduces resistance. This has been demonstrated not only in water, but also on the example of several blocks of ballistic gelatin.
The video clearly demonstrates the helplessness of classic ammunition in the aquatic environment
The same world record - a supercavitating bullet pierces 4 meters of ballistic gelatin
If the experimenters did not trick with the powder charge, then the supercavitational bullet of cartridge 7, 62x51 DCC X2 was able to penetrate a record 4 meters of gelatin. This is 5-6 times higher than the result of a conventional rifle cartridge.
CAV-X and others
The use of supercavitation for firearms and cannon weapons is not exclusively a Norwegian find. The Norwegian-Finnish company Nammo developed a 30-mm Swimmer ammunition (APFSDS-T MK 258 Mod 1) for the United States Navy several years ago. The main task of this weapon is the prompt destruction of attacking torpedoes or mines floating in the water column.
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Demonstration of the destructive power of Swimmen
A flurry of automatic fire, which is conducted from the ship's weapon module SuW with 30-mm artillery mounts General Dynamics Mk 46 Mod. 2, will allow, with a certain degree of probability, to hit an underwater high-speed target. Alternatively, the Swimmer cannon with "floating" ammunition can be installed on helicopters and successfully used to combat submarines. For this, the projectile has everything: a high initial speed of about 1 km / s, a supercavitating nose and a tungsten carbide core. On average, the reach of objects under water by foreign experts is estimated at 250 meters, which corresponds to the near anti-torpedo defense zone. In the United States, plans were being considered to equip such ammunition and ground equipment involved in the protection of coastal areas, as well as important waterways.
In the application to small arms, engineers from DSG Technology offer a whole range of ammunition in caliber from 5, 56 mm to 12, 7 mm under the general name CAV-X. Naturally, the penetrating ability in the aquatic environment progressively decreases with a decrease in caliber - at 12.7 mm - 60 meters, at 7.62 mm - 22 meters, and a 5.56-mm "floating" bullet is capable of reaching the enemy at a distance of 14 meters. At the same time, I repeat, the bullets are quite ready to work in the air. Currently, the US Special Operations Command is testing two modifications of the CAV-X supercavitation bullet at once - X2 and A2. In the first case, the ammunition is more versatile and sharpened for firing from the air at underwater objects. It is much less than a traditional bullet capable of ricochet from the water surface at sharp angles of attack. A2 is more suitable for special forces scuba divers and is adapted for spearfishing saboteurs, drones and attacking observation devices of underwater manned vehicles. At the same time, no special training for small arms is required - I loaded the "floating" Norwegian cartridges into the store, and forward, under the water. Naturally, none of the DSG Technology bosses reveal the details of the design of such an effective bullet. In addition to the special shape of the sock, it is quite possible that the designers have foreseen the possibility of using propellant gases for a shot. The bullet seems to be equipped with a miniature gas generator, which makes it possible to create a steam bubble at the initial stages of movement in the water. This idea was expressed on the popularmechanics.com portal, but how much it corresponds to reality is unknown.
Among the "side" effects of floating bullets from Norway, one can single out good armor penetration due to the carbide core and high penetrating ability. We can say that the CAV-X is a kind of humane weapon of the XXI century. Everyone probably remembers about the scandals in the second half of the last century associated with the high trauma of calibers 5, 45 mm and 5, 56 mm. Bullets in human flesh began to spin wildly, then crumble into separate fragments - all this, together with a high speed, left terrible wounds. There have even been attempts to legally prohibit the use of such analogs of "dum-dum" at the international level. But billions have already been invested in the development of production, and ammunition remained in the arsenal. Largely for this reason, classic bullets are so helpless against underwater targets - the bullet “thinks” that it has hit the body and begins to rotate. Supercavitating CAV-Xs are devoid of these advantages and will easily and easily pass the enemy right through, and maybe even those standing behind will be hit. It is clear that the stopping effect of such bullets (especially in the version 5, 56 mm) is small. At the same time, the CAV-X turned out to be expectedly effective against targets protected by a layer of sand or other porous material - the bullets do not change the trajectory of movement and are capable of piercing a couple of bags without a catastrophic loss of energy. Perhaps large-caliber bullets will be able to effectively penetrate gabions filled with sand, variants of which are already entering the Russian army (in particular, they are being tested in Syria). Another signal from the far abroad that makes you think.
