Even the most stubborn adherents of the AR-15 will not dispute that the Kalashnikov assault rifle has set the highest level of reliability. Therefore, there are a lot of videos on the network in which various combinations of Stoner's alterations are smeared with mud, sprinkled with sand or dipped in water, after which the testers proudly shoot the store, considering this to be a demonstration of their high reliability.
Of course, smearing with mud is not soaking in a swamp slurry, backfilling with sand is not dragging an automatic machine attached to a car along a dusty road, and dipping into a barrel of water is not a long soaking in a bath or exposure to rain. Real tests are longer and more serious than in commercials.
Rabies
In the AK-47, the problem of hydrophobia was not. Soaking is a routine procedure when passing tests, both at the stage of the competition and in the acceptance tests at production. The problem arose when switching to a new smaller caliber cartridge. The water that got into the barrel no longer poured out of it by gravity. To get rid of it, the AK-74 needed a few seconds of vigorous shaking. If this is not done, then shooting with water in the barrel led to a sharp jump in pressure, and this, in turn, led to several defects: it broke the sleeve in the ejector region, knocked out the primer or made it a notch opposite the hole of the striker. The burrs of the notch fell into the gap between the wall of the hole and the striker and wedged it.
For me, some of the numbers that the customer laid down in the technical requirements for the machine will forever remain insoluble. For the AK-74, it was assigned to withstand six shots with the barrel completely flooded with water within the total resource. Why not four or eight? The barrels of artillery pieces, for example, are checked only for one-third filled with water.
Be that as it may, the designers coped with the task brilliantly. First of all, the cartridge was changed by thickening the wall of the sleeve at its bottom. The design of the ejector in the bolt was made in such a way that it closes in the locked position with the bolt frame. The perforation of the capsule was also eliminated by a design change: the striker's exit beyond the shutter mirror was increased by 0.15 mm, the tolerance for the gap between the striker and the wall of the hole, on which the chamfer was introduced, was reduced, and the striker's shape was changed.
What I had in three sentences required several months of hard work, sorting through several options, which were all made in metal, and control shooting through a full cycle of tests. This, incidentally, refers in general to the large amount of work that was done to create the AK-74, and some believe that it was created by simply reinstalling the barrel for a new caliber. After solving this problem, there were no other problems related to water in the Kalashnikov assault rifle.
Four cubes of fluid are enough in the barrel of an M16 to incapacitate it. The main "striking" factor when fired with water in the barrel is the pressure jump of the powder gases. Moreover, depending on the accumulation of water - before, in the area or after the gas outlet, a different type of failure will occur.
If the lugs of the bolt withstand such a jump, then their small plastic deformation still occurs. This is the so-called upsetting of the shutter, which over time leads to an increase in the headspace of the driver, ultimately to rupture of the liner.
But besides the water in the barrel, there is another "wet" problem - soaking. In commercials, weapons are dipped into water, often with the muzzle downward, so that it does not fall into the barrel. This takes into account the very capillary effect, which is usually associated with the fact that water from the well flows poorly. With the same success, it does not flow well. And not only in the barrel, but also in the cavities and gaps inside the receiver. Therefore, the real test with water is not just a short dip. The weapon is kept for a long time under a sprinkler or in the cold, after which it is brought into a warm room and the resulting condensate fills all possible cracks and cracks.
It seems, but what is the matter that water flows into the cavities and wets the surfaces inside the weapon. Here's what. If two surfaces, separated by a thin layer of water, move in different directions at low speed, there is no problem. The picture changes if this speed increases. Turbulence occurs in a thin layer of liquid - areas in which pulsating chaotic jumps in pressure, temperature and changes in the direction of water flow occur. Even short-term cavitation is possible at very high speeds. As a result, a thin layer of water begins to work like a thin layer of sand. In the AR-15, such interlayers are located between the bolt carrier and the receiver body, between the bolt and the bolt carrier, and even between the striker and the hole in the bolt.
There is a place for entropy to roam. What happens if water gets into the cavity behind the recoil buffer and not all of it flows out right away? The dynamics of rollback and rollback of the bolt carrier will change. And if the water is sea water, with salt, which will start to stand out immediately during the shooting? But, perhaps, the crown of the disgrace will be the ingress of water into the cavity of the bolt carrier and then the water hammer will destroy not only the frame itself, but also the body of the receiver with knocking out the store.
The famous "hanging" of the parts in the Kalashnikov assault rifle works not only against dirt that got inside the receiver. The absence of large-area contacting moving surfaces does not give room for stagnant water.
Looking ahead, it is worth saying that replacing the gas outlet with a piston pusher, as done in the HK416, eliminated the problem of water hammer, but threw another one. This will be a separate discussion. Take your time to comment. Better watch the first video from start to finish, then this one:
and see how gullible people on both sides of the Atlantic are fooled.
These guys started to prove that if you smear a Romanian machine gun with mud, it won't shoot. And if you do the same procedure in the AR-15, then nothing will happen to it. Everything would be fine if the inside of the Romanian was not blackened with soot soot.
It seems that these weapons have never been cleaned at all. In order for him to jam the bolt carrier, it is not necessary to smear the whole machine gun with mud, it is enough to shoot a little more. And after that, what is the attitude to the most democratic and just nation in the world?
