Every one with a television knows that a silencer is a device attached to the barrel of a firearm which reduces the amount of noise and visible muzzle flash generated by firing.
These Silencers are typically constructed of a metal cylinder with internal baffles to reduce the sound by capturing and slowing the escaping gases.
Like most things, suppressors, as they are more correctly know, are more complicated that that. Since 1934, silencers, as they are called in the National Firearms Act (NFA) are regulated. There is pending legislation, the Hearing Protection Act (HPA) which seeks to remove silencers from the NFA to mitigate the costs of hearing loss. US Special Operations Command has provided their forces with suppressors and the Marines are experimenting with suppressing all of their weapons.
The NFA was originally enacted in 1934. Similar to the current NFA, the original Act imposed a tax on the making and transfer of firearms defined by the Act, as well as a special (occupational) tax on persons and entities engaged in the business of importing, manufacturing, and dealing in NFA firearms. The law also required the registration of all NFA firearms with the Secretary of the Treasury. Firearms subject to the 1934 Act included shotguns and rifles having barrels less than 18 inches in length, certain firearms described as “any other weapons,” machine guns, and firearm mufflers and silencers.