Copyright © February 2016 Violence Policy Center

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Silencers are devices that are attached to the barrel of a firearm to reduce the amount of noise generated by the firing of the weapon. By providing a larger contained space for the gases generated by the discharge of the gun’s ammunition round to dissipate and cool before escaping, silencers reduce the sound generated by the weapon’s firing.

Since 1934, silencers have been regulated under the National Firearms Act (NFA).1 The NFA requires that transferees of silencers submit fingerprints and a photograph, pay a special tax, and undergo a background check. It also requires a “Chief Law Enforcement Officer” or CLEO to sign a statement confirming that a certifying official is satisfied that the fingerprints and photograph accompanying the application are those of the applicant and that the certifying official has no information indicating that possession of the silencer by the applicant would be in violation of state or local law. In January 2016, however, the Obama administration finalized a new rule that eliminates the CLEO sign-off requirement and replaces it with a requirement that local law enforcement need only be notified of the transfer of a silencer. The rule is awaiting final implementation.

Hiram Percy Maxim is credited with patenting the first silencer in 1908. But a short time later their utility in crime was demonstrated in a tragic murder-suicide on Central Park West in New York City in 1915.

In the decades that followed, silencers were used by the Office of Strategic Services (OSS) during World War II for clandestine missions. Silenced handguns were also used in Vietnam for multiple purposes. According to a Former Special Forces NCO, military units used suppressed pistols “for all sorts of sneaky ops, from dumping guards to out and out assassinations.”2

In 1967, a new generation of silencers was developed by Mitch WerBell for Sionics, a company that specialized in counterinsurgency equipment. The acronym Sionics stood for Studies in Operational Negation of Insurgency and Counter Subversion. The company supplied silencers and similar items for covert operations by military and “CIA-type” clandestine organizations.3 These next-generation silencers were more efficient than their turn-of-the-century predecessors and could effectively be used on battle rifles and Carbines. Today’s military silencers are used by special operations units to reduce noise and muzzle flash.


1 Examples of the types of firearms that must be registered under the National Firearms Act [26 U.S.C. §5845] include: machine guns; the frames or receivers of machine guns; any combination of parts designed and intended for use in converting weapons into machine guns; any part designed and intended solely and exclusively for converting a weapon into a machine gun; silencers and any part designed and intended for fabricating a silencer; short-barreled rifles; and, short-barreled shotguns. Also included are “destructive devices.” These include Molotov cocktails, anti-tank guns (over 50 caliber), bazookas, and mortars. “Any other weapon,” which includes cane guns and other gadget-type firearms, such as “pen” guns, which fire a projectile by the action of an explosive are also regulated under the NFA.

2 “The Ruger/MAC MKI: Vietnam’s Silent Service,” Small Arms Review, May 2005, accessed October 30, 2015 from

3 “Sionics Incorporated,” Small Arms Review, November 2011, accessed October 27, 2015 from For more detail on Sionics and the use of silencers in Vietnam, see “Silencers: the NRA’s latest big lie,” Salon, December 30, 2012.

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