A suppressor is a device attached to or built into the firearms barrel system that reduces muzzle flash and sound generated by firing the gun. These suppressors work by slowing the propellant gasses emitted from the bore as the bullet exits the barrel using baffles or wipes redirecting or delaying the gas movement which reduces the sound signature. Some firearms with suppressors can reduce the sound signature to such a low level that it almost seems to be silent except for the moving action of the firearm. This sound reduction is also affected by the type of cartridge fired from the gun, such as sub-sonic rounds that are much quieter than full power loads.
The “can” type suppressor is usually detachable and can be used on more than one firearm. The integral suppressor is built as part of the firearm as part of the barrel assembly. These modern style suppressers work under the same principle by diverting or trapping the expanding gasses inside a series of hollow chambers. The trapped gas expands and cools as its pressure and velocity decrease due to reduced volume as it exits the device. The suppressors use baffles or wipes to divide the cylinder into chambers of at least four, but could be 4 or 5 times that many depending on the design and caliber.
There is five major categories defining suppressed fire noise: action, blast, sonic signature, impact and operator. Some are present in all instances, while others depend on the mechanics of the firearm. When a weapon is fired, there can be multiple sounds possibly apparent. Here they are in order of shot timing:
- Action noise to ignite the cartridge.
- Muzzle blast from the discharge of propellant gases out the end of the barrel.
- Sonic signature of the projectile in flight (supersonic).
- Action noise in firearm variants as casing is ejected and new cartridge is chambered. (Bolt and Action movement)
- Impact noise created as the projectile strikes target.
Of these, the most noise is usually the muzzle blast and sonic signature. Two sound reports from the same shot may be hear when the listener is reached by the shock wave generated by the bullet flying past at supersonic speed, and then the muzzle blast following it. Attempts to harness these sounds are made while the manufacturer builds the suppressor according to their design. Always check with the manufacturer for decibel reduction ratings on their suppressor models. Some are better than others. Caliber can play a major role on the effectiveness of individual brands of suppressors. Read more here on ATAC TV Firearms Blog