Why do some machine guns have trumpet-shaped muzzles?

The trumpet-shaped muzzle is a flash suppressor. Let’s first talk about where the muzzle flame comes from. The muzzle flame is also called the muzzle flame. It is the high-temperature and high-pressure gunpowder gas flowing from the muzzle. It is a visible light produced by thermal radiation and mixed combustion with flammable gas. This light We can divide it into 5 stages according to space and time, which are the early flame, the primary flame, the muzzle glow, the intermediate flame, and the secondary flame. Because the early flame, the intermediate flame, and the secondary flame have a certain degree of independence, so It is the main target of the flame suppressor.

(MG-42 general machine gun) What we want to suppress the occurrence of flames is mainly to avoid and limit the shock wave heating and combustion generated by the gunpowder gas at the muzzle, so the principle of the flame suppressor is also very simple. First, use The gunpowder gas is fully burned, reducing the pressure and temperature at the outlet. This process mainly reduces the primary flame, because the primary flame is generated due to the high temperature and pressure of the gunpowder gas, which radiates the visible light, and then passes through The special horn-shaped structure of the flame arrester is used to reduce the mixing and combustion process with the surrounding air. At this stage, the intermediate flame and the secondary flame are mainly eliminated.

(ZB-26 machine gun)

So not to mention today’s highly developed detection technology, the problem of muzzle flame was also a big problem during World War II. For example, the famous weapon given to the Allies in World War II The German MG42 general-purpose machine gun that was severely damaged by the military, the ZB-26 light machine gun that served as the backbone of my country's firepower during the Anti-Japanese War, and the Japanese Type 99 machine gun all use bell mouths to eliminate flames.

(Japanese Type 99 machine gun)

Trumpet-shaped flash hiders are divided into two categories, one is a cone-shaped hood, and the other is a cone-shaped flash hider. They are actually about the same length. The conical hood has a larger cone angle than the conical flash suppressor and is shorter in length. The advantage of this structure is that it can weaken the primary flame and muzzle glow, but it has no effect on the intermediate flame and secondary flame. Remarkable, so later this structure was gradually replaced by cone-shaped flame arrester. The cone-shaped flame arrester, due to its small cone angle and long length, not only inherits the advantages of the cone-shaped hood but also solves the shortcomings of the cone-shaped hood. It can not only eliminate the primary flame but also eliminate and weaken the intermediate flame. and secondary flames. Due to the intensity of the microwave and the angle of the cone angle, generally speaking, the angle of the cone angle is between 8 and 20 degrees. At the same time, in order to improve the flame suppression effect, many small holes will be opened in the wall. In addition to conical flame arresters, there are many types of flame arresters, such as cylindrical flame arresters, cylindrical flame arresters, fork-shaped flame arresters, and combined flame arresters.