Often times, the term muffler and silencer are both used to describe the same thing. Mufflers and silencers both reduce the ability to detect that a weapon has been fired. For instance, a silencer placed on a gun can make the sound of the gun being fired undetectable, even to those close by to the shooter.
Silencers are attached to the barrel of a gun. The silencer acts by reducing the speed of gas that escape the gun, thereby reducing the sound. In addition, silencers reduce the velocity of a bullet or other form of ammunition, as it passes through the chamber and barrel of a weapon.
Silencers were originally called mufflers and still are in some parts of the world. The man that invented the silencer, also invented the muffler for cars. Both inventions were meant to silence or muffle the noise produced by a mechanism. In fact, the term suppressor also refers to the same item.
Silencers, suppressors and mufflers can all be used to reduce the sound of any mechanical item, such as vehicles, guns and other weapons. The ability to reduce the noise from a weapon can be life saving, especially in battle scenarios. Soldiers that are in battle can fire their weapon without being detected by the enemy. In fact, snipers often use silencers to be able to fire accurately from a distance, or even when they are close to the enemy, in order to avoid detection.