Super gigantic silencer used for tank gun etc

In a movie, etc., there is a scene in which a killer sticks a long tube in front of a pistol and shoots the target with almost no sound, but this cylinder is called a silencer (muffler). It acts to soften the shock wave at launch, but in Germany this seems to be applied to huge fire like guns of tanks.

Details are below.
German Artillery silencer !! - WW 2 in Color History Forum

German heavy weapon maker's munitions companyLine Metal CompanyAnd Acoustic Engineering LaboratoryIf LThis muffler developed for weapons research facilities etc. to reduce noise to the surroundings as much as possible. Basically it is used for deferred use, it is not supposed to be used in actual battle.

At the 91 Weapons Technology Center in Germany · MeppenM109 155 mm self-propelled grenade gunUnder test.


A mechanism to reduce the sound by slowly releasing the high-speed gas that comes out during launch in the body once.


The protrusion perpendicular to the barrel direction,Muzzle brakeIt is to receive fire gas from.


Looking from behind like this.


Line Metal, IfL, vehicle manufacturerMan CompaniesDeveloped(PDF file)prototypeThe material is here.

The prototype is the main tank of the German armyLeopard 2It was done with 120mm cannon.


The bullets escape from the near side to the back.


It is like this when taking out contents. The shooting gas collides with this silver rod shaped part, and energy is dispersed.


By doing this, the bullet goes forward from the center, but the gas decelerates while moving through the tank and is made to go out gradually.


The front part is partitioned like this, so that the gas is hard to go out.


Result of frequency measurement. You can see that the sound reduction in the bass part around 10 Hz is large.


About 20 dB of attenuation was observed throughout the range of sound pressure measurements by distance.


Directivity pattern of sound. The attenuation of the sound to the rear is large, but it seems that the sound is a bit easier to reach in the forward direction.


Where we actually shot. First of all, once large launch gas comes out, then gas gushes out again, then gas will gradually take time.


In the graph on the left, the energy of the shooting gas is concentrated at one time, whereas in the measurement result using the muffler on the right side, it is decomposed into fine waves and the peak is lowered I understand.


Additional notes:
Although it is pointed out that it is not a silencer but a suppressor (silencer), we have used "silencer" which is a common notation in the sentence.

In a general sentence in the English-speaking area, "silencer" notation is preferred, and also when it is called "suppressor", it seems that there are many cases where "silencer" is often written together. A public agency in the United States is also a "silencer" notation, for example, regulating the possession of mufflersArticle of the Federal Firearms Act of the United StatesBut that's it.

On the other hand, for firearm manufacturers and actual users, it seems that it is more preferred to use the same kind of equipment as "suppressor" as a more practical expression.