A sound suppressor, or just “suppressor,” is designed to reduce the noise caused by a firearm. While often called a “silencer,” it doesn’t actually fully silence a weapon although it can drastically reduce the sound profile of a weapon being fired. In addition to reducing the noise, a suppressor can also help reduce the visible flash that results from a weapon being fired.
Suppressors are usually constructed of a metal cylinder. They feature internal baffle components that help slow and cool the propellant gas, therefore decreasing the muzzle blast and intensity of the sound. A flash suppressor, however, is specifically designed to cool and disperse burning gasses exiting the muzzle without any control over reducing the sound.
While suppressor is a much more accurate term, the United States Department of Justice and the United States ATF (Bureau of Alcohol, Tobacco, Firearms and Explosives) both refer to suppressors officially as “silencers” which has led many civilians and other organizations to do the same. The initial cause of this was that the first silencer on the market was made by Hiram Percy Maxim who marketed them as “Maxim Silencers”. The term “suppressor” was not used until a patent was filed in 1985.
Today, the use of a silencer is illegal in multiple locations. For instance, the Danish Weapons and Explosives Law made them illegal in Denmark to possess without a license. However, this was revised in 2014 to make them legal for hunting purposes. Other countries have also taken steps to regulate the suppressor, with Canada considering it a prohibited device that cannot be owned or imported by civilians. In the United States, they remain legal in 42 of the 50 states with certain regulations (requiring a $200 fee and a background check to legally purchase one).