Usually in weapon reviews I try to at least briefly describe how automation works, but sometimes there are several articles in a row about weapons with the same automation system as a result, writing the same thing is not at all interesting, and I don’t always want to describe in detail what and where is moving. In this material I want to cover at least what has been and is being used in firearms at the moment, naturally with concrete examples. The material will be big, sometimes tedious, I will try to write without the use of terms, that is, roughly speaking, I will explain on my fingers. So who in the subject can safely skip the article, because you will not learn anything new from it, and who wants to figure out how and what works, then it is necessary to read it. May be added new visitors due to this article in the sections "Individual weapons" and Sniper weapons ", otherwise we sit here with our company, we will expand.
Automation system with free shutter.
Let's start with the simplest, namely with the automatic shutter system. The Makarov pistol will be the closest example to our compatriots; besides, the free bolt is often used in machine pistols and in those models that use low-power ammunition. In pistols, the free bolt is mainly used with cartridges with a small kinetic energy of a bullet, the limit for such a system can be called 9x19 ammunition, for which there are several models of automatic pistols with a free gate. But such a weapon works, in the literal sense, at the limit of its capabilities, because of which its resource is very small, and the requirements for the quality of materials are very high, which naturally affects the cost. If we talk about submachine guns, then in them the automatic system with a free gate is used more widely and with a wide variety of ammunition. But first things first.
Automatic system with a free gate for pistols.
We will analyze the automatic system with a free gate for pistols using the example of the same PM, as for people interested in weapons there is always an opportunity to get acquainted with this gun due to its wide distribution, at least in the “traumatic” version, which does not differ from the original automatic system . Inside the casing of the weapon, the same part that is being pulled to move the cartridge from the magazine to the chamber, the uppermost moving part of the pistol, is the shutter, because for most of the pistols in the description they say not just the shutter, but the shutter-casing, as these are two parts rigidly interconnected. There are variants of pistols, where the bolt is represented by a separate piece of its own, but there are few of them. Despite the fact that the automation system with a free shutter, the shutter is actually not that free, its movement is hampered by the return spring of the weapon, which is wound around the barrel in a Makarov pistol. The return spring abuts against the front of the casing-bolt, so that in order for the casing-shutter, and accordingly the shutter itself to be in its extreme rear position, it is necessary to compress the return spring. And now how it all works.
As is known, the bullet moves along the bore due to the fact that the powder during its combustion releases combustion products in a volume that is much higher than the volume of the powder itself. Due to this phenomenon, the pressure between the cartridge case and the bullet increases very quickly, and accordingly a larger volume is required to reduce this pressure. The increase in volume free for powder gases occurs precisely because the bullet moves along the barrel and the distance between the cartridge case and the bullet increases. To make it more clearly you can present all this in the form of a piston, but with one reservation. Powder gases, expanding, put pressure not only on the bullet itself, but also on the walls of the bore, as well as on the bottom of the liner. If the sleeve did not support the bolt, it would fly out of the chamber in the same way as the bullet, but since the weight of the bolt, casing and sleeve is greater than the weight of the bullet, and plus the whole casing-gate does not allow the return spring to move freely, the sleeve remains in the chamber.
It is quite timely to ask how the recharge occurs in this case. I will try to explain back on a simpler example. If you take two metal balls with a big difference in mass and put a compressed twisted spring between them, then when the spring straightens and pushes the balls, they will move at different speeds, and if the difference in weight is very large, then one of the balls can remain on place In our case, to ensure trouble-free and proper operation of the weapon’s automation system, it is necessary to ensure that the bolt-cushion is moving after the bullet leaves the barrel, that is, that it is not powder gases that push the barrel with the bolt its mass preserved energy obtained through the sleeve from the powder gases, pulled the sleeve from the chamber.
I feel heaped up the forest, “imagine that, imagine it”, because a lite-version of the description of the automation system operation with a free gate:
When fired, the powder gases expand, push the bullet at high speed through the barrel bore, press against the sleeve, which transfers the energy received from the powder gases to the shutter. Due to the greater mass of the casing-bolt, in comparison with the bullet, its speed is much lower than the speed of the bullet, but due to the greater mass, the casing-bolt picks up speed more slowly, because it is often said that the casing-bolt begins to move after the bullet has left barrel that is not quite right. Thus, the automation system can be represented as a system with two movable pistons in one cylinder, differing in the effort necessary for their movement. Well, speaking roughly and do not take into account the fact that one of the pistons continues to move even when the second one jumped out of the cylinder, and the pressure in it returned to normal.
Well, in order to make it completely clear, we will try to go through the points of what happens when fired by the example of a Makarov pistol:
1. The powder ignites, begins to burn, increasing the pressure between the sleeve and the bullet.
2. The bullet moves along the barrel, picking up speed, the shutter-casing begins very, very slowly, almost imperceptibly, to accelerate.
3. The bullet leaves the barrel of the weapon, the bolt continues to move due to its mass, even though nothing pushes it through the sleeve anymore. In the process of movement of the shutter is constantly compressed return spring.
4. The shutter casing removes the cartridge case from the chamber and throws it through the window for the cartridge case.
5. Having reached its rearmost point, the casing of the bolt cocks the gun trigger and stops
6. Since the return spring is compressed, after the casing-shutter stops, it tries to straighten up, as a result, the casing-shutter begins to move forward.
7. In the process of moving the cover-shutter, a new cartridge is removed from the magazine, which is simply pushed forward.
8. The shutter casing inserts a new cartridge into the chamber and stops.
Despite the fact that everything is really very simple, even such an automation system may not work correctly. Above was given an example with two metal balls of different mass, between which a compressed spring was laid. Just this example most clearly demonstrates two options for the improper operation of the weapon automation system. In the first variant, when one of the balls is too heavy, in comparison with the second, it simply will not budge. In our case, this will mean that the shutter-casing will simply prop up the liner and recharge will not occur. In the second case, the automation system does not work with a free gate, the shutter can start moving even before the bullet left the barrel, respectively, the thin walls of the sleeve will take the whole “blow” from the powder gases to themselves and most quickly fail or withstand. Both of them are not good for us, since a deformed or torn sleeve can jam the cover and slide, and the powder gases burst through the broken sleeve, instead of pushing a bullet through the barrel, will simply go slower.
It may seem that ensuring the proper operation of the automation system is an incredibly complex task, connected with an accurate calculation of the weight of the housing-gate, but this is not so. In the case of balls of different mass, between which a compressed spring is laid, we can really “play” only with weight and with nothing else. In the case of a gun, we have another opportunity to act on this system, namely, through a return spring. Since the return spring is directly connected with the shutter casing, by changing its rigidity, we can also change the speed of the casing-shutter, without changing its weight.
Naturally, examples of the improper operation of the automation system cannot be found in military weapons, since such samples are designed by specialists and such “childhood diseases” are a disgrace for the designer. Yes, and military ammunition for its energy is more or less stable. It is possible to meet the improper operation of the automation system with a free gate in pistols except in very old samples or in case of outright marriages in the manufacture of weapons or ammunition. But to look at this mess is an opportunity. Provided this opportunity traumatic weapons. Immediately I would like to say that the reason for the malfunctioning of the automation system with a free gate in the traumatic system is not a mistake in the design of the weapon. The true reason is that the traumatic cartridges have a very large difference in their kinetic energy. Here is an example. The weapon is designed to use sufficiently powerful ammunition, the seller decided to sell very weak cartridges to the gun owner, praising them and calling them ideal for training firing, and that's the inscription on the box “Training”. Having decided to shoot and hone their skills, the owner of a pistol unexpectedly discovered that he had turned the gun from self-loading into a weapon with a manual reload, because the energy of weak cartridges is not enough for the bolt to go all the way back. Naturally, the gun and the manufacturers are “guilty” of this, but if you replace the return spring with a weaker one, everything will work like a clock. Or the opposite example. Weapons, designed for weak ammunition, charged more powerful. As a result, when the cartridge case is similar to shooting, it is not clear what, and the gun itself periodically refuses due to stuck cartridge cases. We omit the point that in weak samples not only the automation system is designed to use weak cartridges and the use of more powerful ones will lead to weapon breakage, but in this case a more rigid return spring will ensure reliable operation of the automation system, although not for long.
In general, the automatic system with a free gate proved itself in the pistols as the simplest and most reliable, and if it were not for restrictions on the power of ammunition, the free gate would have become the most common in the pistols. However, they were once the most common when self-loading pistols just appeared.
Automation system with a free gate for submachine guns.
In pistols, machine-guns, the free bolt, which occupied its leading place in distribution, continues to occupy, although other automation systems try to press it while the leadership remains behind it. The reason for this spread is not in the fact that only low-power cartridges are used in the free-gate PP, this is a much greater variety of ammunition, but because the designers have found solutions that were unacceptable in pistols.
The simplest solution to the problem is the long stroke of the shutter. Everything works in the same way as in pistols, but at the same time the bolt has a longer stroke, which reduces the load on the parts of the weapon. In pistols, unfortunately, it is difficult to apply, as the dimensions of the weapon will increase dramatically. An example of such an automation system can be the domestic submachine gun Kedr, which can also be seen on the example of its traumatic version of Esaul, although it is not very common and deprived of the opportunity to conduct automatic fire, so that acquaintance is incomplete.
Much more tricky way is the automation system, in which the shot comes from the open shutter. In the previously discussed variants, the normal position of the bolt before a shot is its frontmost, when it rests against the breech breech, in this case everything is exactly the opposite. The normal position of the shutter is its rearmost, with a compressed return spring. Thus, when a shot is fired, the bolt is released, on its way forward, it picks up the cartridge from the magazine, inserts it into the chamber and breaks the primer.
Such an automation system has its advantages and disadvantages. On the positive side, it is worth mentioning the fact that sufficiently powerful ammunition can be used in weapons while maintaining a relatively short stroke of the bolt. This happens because in order for the shutter to start moving in its opposite direction, it must first be stopped, that is, a part of the energy of the powder gases is spent on stopping the shutter and a part so that it starts moving backwards. The negative quality is that the moving parts of the weapon knock it from the aiming point before the shot, therefore, the weapon becomes less accurate. I'll try to write down the points, how it all works.
1. The shutter is in the rearmost position, the chamber is empty, the return spring is compressed.
2. The bolt begins to move forward, picks up a new cartridge from the store.
3. The bolt inserts a new cartridge into the chamber and breaks the primer.
4. A shot is fired, powder gases push a bullet through the barrel, and the bolt is braked through the sleeve.
5. Shutter stops
6. The shutter, receiving energy from the powder gases through the sleeve, begins to move backwards.
7. The bolt pulls the cartridge case from the chamber and throws it out.
8. Having reached its rearmost point, the shutter stops, compressing the return spring (for a single fire mode).
In general, everything is simple, you can even say that everything is the same, just the numbering of the actions was shifted. An example of the use of such an automation system can be at least PCA. The free shutter automation system is inherently the first automation system on the basis of which the first self-loading weapon models were made, so that it can be said that this system is one of the oldest. Despite all its limitations on the power of ammunition, it still remains a fairly common system, and its reliability and ease of production make many gun manufacturers pay attention to it.
Fixed shutter automation system.
Unlike the previous automation system, the fixed shutter is very rare, one can even say that it does not occur at all, but since such an automation system exists, it cannot be missed, especially since it, just like the previous one, does not lock the bore rigidly so they are somewhat similar. At the same time, an automatic system with a fixed shutter is a kind of exception, since all the other options used in self-loading weapons cannot do without it. Weapons with a similar automation system are very, very few, the most famous is the gun Manlichera M1894.
It is not necessary to paint this automation system for a long time, everything works very simply and clearly. As you know, there are rifling holes in the barrel bore, and the bullet itself must pass tightly enough along the barrel bore to maximize the use of powder gases. Thus, if the barrel of the weapon was mobile, then when fired, the bullet would push it forward due to the friction force that occurs when it passes through the barrel. It is on the basis of a rolling barrel and fixed-gate automatics works. In other words, instead of using a mobile gate for reloading, pushed by the energy obtained from the powder gases, a completely different principle of operation was used, in which the powder gases, although participating, do not have a direct relationship to the automation system. It all works as follows.
1. When the powder charge ignites, the bullet begins to move along the barrel, pushed by the powder gases, while the barrel of the weapon, having a greater mass than the bullet, also begins its advance, but this is almost imperceptible.
2. The bullet leaves the barrel of the weapon, and the barrel itself, having received enough energy from the bullet to roll forward completely, begins to move, compressing the return spring.
3. The barrel goes forward, freeing the cartridge case, which falls out, having received the long-awaited freedom, independently, or else pushed by a spring-loaded element.
4. The barrel reaches its extreme front point, maximally compressing the return spring.
5. Under the action of the recoil spring, the barrel begins to move back, while it picks up a new cartridge from the chamber.
6. The barrel rests on a fixed bolt and the weapon is ready for the next shot.
As is clear from the description, there is nothing difficult to associate a moving barrel with a gun trigger, for its automatic cocking, well, or to introduce a double-action firing mechanism. This automation system is quite interesting and simple, but its implementation requires a very precise fit of parts, in particular, the barrel and frame, so that the movement of the barrel does not affect the accuracy of the weapon. Naturally, the durability of the weapon will depend on the quality of the materials used, and in this case it is in any case subject to very rapid wear. Thus, weapons with such an automation system will need constant lubrication, will be very susceptible to contamination and will not last long, even with the highest-quality production. Actually this was the reason that weapons with a similar automation system are very rare.
For the first part of the material on weapons automation systems, I think that will be enough, and there is still a lot of interesting things ahead.
PS The first photo is not a suicide club, people have ice cream in the form of pistols in their hands.