A sound suppressor is designed to be most effective with a specific firearm and cartridge combination by reducing the muzzle blast, which is the most significant portion of the noise. Muzzle blast is caused by high pressure propelling gases in the bore suddenly escaping into the atmosphere as the bullet exits. Reduction of the pressure results in decreased noise. How well a given suppressor achieves these goals on a given weapon depends on how efficiently these objectives are achieved.
T here are two basic types of firearm sound suppressors.
The most common and oldest historically is the muzzle suppressor which attaches to the muzzle of a firearm, either by threads or a coupling device. The other type found today is the integral suppressor, which is built around the barrel of a firearm and incorporates characteristics of both the muzzle and barrel suppressor. With today's technology and the availability of reliable commercial subsonic ammunition in both 9mm and .22 rimfire, the efficiency of a muzzle suppressor is comparable to that of an integral suppressor. The primary advantage of a muzzle suppressor is that it may be moved from weapon to weapon and does not require dedicating a firearm to the suppressor. Furthermore, there is no reduction in kinetic energy of the projectile through velocity control as is the case with integral suppressors.