Sound suppression (Silencer)is one of the more interesting facets in the study of firearms technology. How do we make something that is inherently loud seem relatively quiet? If you've watched as many movies as I have, you may have a few misconceptions about suppression, or you may just be interested in how it works. no firearm can be truly silenced; there will always be some sound associated with the discharge of a firearm. Therefore, use of the term "silencer"a suppressor is designed to protect the shooter's hearing without the need of more conventional hearing protection devices, such as ear plugs or muffs. In general, any suppressor manufactured is designed to bring the sound pressure level below the threshold of pain, or 141 decibels. In this case, the sound of the gunshot may still be recognizable; it just isn't as loud. There are three basic origins of noise that need to be considered in order to suppress a firearm. These are sometimes called the "Holy Trinity" of firearm sound suppression. The first and loudest is muzzle blast. "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. Pressure is reduced by increasing the volume for gas expansion, reducing the gas temperature (cooling), delaying gas exit through trapping and turbulence, and by a combination of these technologies. How well a given suppressor achieves these goals on a given weapon depends on how efficiently these objectives are achieved."¹ The second is the ballistic crack created by a bullet as it enters the transonic zone and continues on to supersonic flight. The third is the sound of the weapon itself. On its own, the sound of the hammer or striker being released causing the firing pin to strike the primer cap of the cartridge is represented by a "click" sound, almost identical to that of a firearm being dry-fired Other suppressor designs attempt to make it as difficult as possible to tell that a gun has been fired at all.A suppressor initially contains and then releases combustion gases slowly, similar to the way you'd untie the balloon and allow the gases inside to escape at a slower rate, reducing noise. Dry suppressor includes a primary expansion chamber followed by series of metal baffles. Some designs include a series of secondary expansion chambers between a series of baffles (i.e., primary chamber, three baffles, small chamber, three baffles, etc...). This type of suppressor is most commonly found in use on .22 rimfire pistols, rifles and most fully automatic firearms. Maintenance can be performed less often compared to other designs. The suppressor can be designed to bleed the excess propellant gases before the bullet reaches the muzzle of the weapon, in effect slowing the bullet to below supersonic speeds before it exits the muzzle.