Among the factors that limit the combat capability of infantry, the weight and volume of bullets have always been a headache. If the bullet belt is short, the soldiers will be restrained when fighting, unable to give full play to the firepower advantage, and passive everywhere; and if the belt is too large, the soldiers cannot run.
is very natural, people began to think about the structure of the bullet, to remove the bullet shell, which occupies a large part of the weight, but does not directly contribute to the kinetic energy of the bullet. The profile structure of
traditional ammunition. Note that the gunpowder in the primer has been removed for safety reasons. The most basic purpose of the
cartridge case is to combine the primer, propellant, and warhead that ignite the propellant into a closed unitary structure. This greatly improves the speed of the shooter's loading of ammunition, and will not cause the primer and gunpowder to fail due to rain and other problems, so that the firearms can be used all-weather. Picture of
: The structure of the German G11 shell-less bullet, with gunpowder bonded together on the outside of the warhead. Although great efforts have been made to prevent spontaneous combustion, it still fails to meet the basic safety requirements. When
is developing a caseless ammunition, people adhere to the propellant into a monolithic structure, wrap the warhead and primer, and add a coating or combustible film on the surface to isolate water vapor and other influences; successfully without the use of the case. , Still achieved the integration of ammunition structure, solved the problem of loading, and obtained environmental reliability close to traditional ammunition.
Picture: The firearms and ammunition of the German G11 rifle. Note that its magazine is mounted on the top and front of the gun. The
Picture: The gun mechanism of the German G11 caseless firearm is too complicated, and it is not completely caseless. The reason is also because of its complicated feed path. But this is only the result of the old problem of the Germans not being able to understand the boundaries between weapons and mechanical crafts, and it cannot represent the normal development route of the caseless firearms system.
And the other role of the cartridge case is very troublesome to replace-it plays a role of sealing off the gunpowder gas and preventing the high temperature and high pressure gas from being sprayed around the gap between the bolt and the barrel.
After canceling the shell, although the shelling and ejection mechanism of the shellless gun can be eliminated; but the bolt system must have its own air-tight capability, which will significantly complicate the overall structure design-not only the cost of manufacturing and assembly is higher, but also Reliability and maintainability will deteriorate.
And the above two problems were all anticipated from the beginning during the development of caseless firearms systems in various countries in the 1960s and 1980s, and they were the focus of the design. Although the cost was very high, the results The performance is not particularly satisfactory, but it can be regarded as reaching an acceptable preliminary practical level.
However, some other functions of the cartridge case were not discovered during the initial needs analysis and demonstration of the project, or were far from being paid enough attention, and finally declared the failure of the caseless firearms system, which has not been able to break through.
Note that the temperature of the cartridge case is much higher than that of any other place. The above
is the slow motion of the pistol firing and shell ejection under the thermal imaging camera. First, pay attention to the ejected cartridge case, its temperature is very high-in other words, the ejection process itself will take a large part of the heat into the barrel and barrel. Secondly, during the shell ejection process, a large amount of high-temperature debris was sprayed from the inside of the barrel to the rear. Among them, the gunpowder residue was incompletely burned, and there were debris generated when the shell of the warhead rubbed against the barrel.
After the use of shellless bullets, the heat dissipation capacity of the chamber deteriorates significantly, and the temperature rises very quickly. For pistols, which have a low rate of fire and small ammunition capacity, it is okay; if it is an automatic rifle or machine gun, after continuous shooting, it is very easy to cause the next bullet to be heated and spontaneously fire after entering the chamber, resulting in a fire accident . And this kind of accident has always been the norm in the test of the caseless ammunition firearms system, and it is also the most fundamental reason why the caseless ammunition firearms cannot be practical.
In addition, the cartridge case prevents most of the high-temperature gas from contacting the barrel when the gunpowder ignites, and during the process of being drawn out and thrown away, it will "scrape away" a part of the attached foreign matter from the barrel due to friction. Without the cartridge case, the degree of foreign matter such as gunpowder residues accumulated in the barrel will become much more serious, which will have a significant adverse effect on the reliability of the loading of the gun bullet.
5.56mm plastic shell ammunition under development in the United States
At this stage, foreign countries are still carrying out research on shellless firearms, but they are still far from practical. Take the United States as an example. The breakthrough work of the new generation of ammunition adopted the two-step plan
, which first studied lightweight plastic shell ammunition and then transitioned to complete shellless ammunition.-
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