Effectiveness of sound reduction of a shot by silencers or sound moderators.

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One of the main characteristics of the quality of silencers (sound moderators, PSUZV, silencer, suppressor) is the level of reduction of the sound of the shot.

In this article, I want to highlight some of the factors that influence this indicator. All the arguments given in the article are my personal opinion, based on a fairly large experience in the manufacture and use of such devices.

Let us dwell in more detail on the mufflers of our company of the ASTUR series. These soundmoderators are designed for use on both slide bolt carabiners and semi-automatic muzzle threaded carabiners. First of all, it should be said that ASTUR mufflers, like other devices of our company, are not a copy of any muffler of other brands. The internal structure of the muffler is an original scheme developed by the specialists of our company and is a classic “direct-flow” seven-chamber scheme with a device for preliminary dissection of the gas flow.

A very convenient example for discussing the factors affecting the effectiveness of reducing the sound of a shot, in my opinion, is the ASTUR muffler with an M14x1 mounting thread designed to work with cartridges of 7.62×39 or 308 caliber.

Silencer ASTUR reduces the sound of a shot from 24 dB to 28 dB (when measured with a sound level meter), which is approximately 60 – 70% (judging by ear) lower than the sound of a shot with a conventional (non-subsonic) cartridge. Speaking about the level of reduction of the sound of a shot, it is necessary to take into account that this value is rather subjective and conditional. It depends on many factors, such as: the shooter’s hearing, shooting conditions, weather conditions, technical capabilities and features of the carbine on which the sound moderator is installed. It has long been known that any muffler is more effective at reducing sound on sliding bolt carbines (we are talking about the shooter’s sensations) than on semi-automatic carbines. This is due to the fact that on bolt sniper and hunting carbines there is no effect of the reverse movement of powder gases. All powder gases generated during firing remain “closed” in the bolt group and can only move forward through the barrel and silencer. In semi-automatic carbines, immediately after the shot is fired, the bolt opens and part of the powder gases breaks through back into the bolt group, reducing the efficiency of the sound moderator. In particular, with the Vz.58 semi-automatic carbine, almost immediately after the shot, the entire bolt moves back and the powder gases, without meeting any resistance, burst into the shooter’s face. At the same time, the muffler works at almost 60% of its capabilities.

Speaking about – “conditions where shooting is being conducted” – I mean by this such factors: open or closed space (as an example of a shooting range or open shooting range), terrain features (field, ravines, forest, hills or mountains). As you know, when using mufflers, we achieve a reduction in the sound of a shot due to “smoothing” the difference between atmospheric pressure and the pressure of powder gases escaping from the barrel. At the same time, in most cases, the shooting is carried out with a supersonic cartridge and naturally no sound moderator can completely remove the sound of the shot. At least there will be a sound from a bullet flying away and an echo from it. Simultaneously with the sound from the bullet, the shooter hears the sound from the shot itself, reduced and redirected by the sound moderator in the direction – more forward from the shooter (in most cases). The presence of any obstacles in front and on the sides of the shooter will cause the reflection of sound waves and, accordingly, subjectively, worsen the level of sound reduction of the shot. The sound spreads especially peculiarly when firing over the water surface.

Speaking about – “weather conditions” – I mean the difference in the speed and nature of the propagation of sound waves in the air, taking into account such factors as: air humidity, temperature, density. Using the same silencer, the shooter will hear the sound from the shot differently when shooting in dry weather or in dense fog. In this case, the tonality of the sound that is produced when “leaving” the sound moderator is very important. In my personal experience, higher pitched sound dissipates faster than lower pitched sound.

Thus, for an objective assessment of the level of reduction in the sound of a shot, the shooter must compare different sound moderators in the most identical conditions (on the same weapon, the same cartridge, the same shooting conditions).

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