5 Surprising Facts About Gun Silencers - Science | HowStuffWorks

Gunshots are loud because superheated gases expand rapidly and produce shockwaves as they escape the gun's chamber. Silencers contain a series of expansion chambers that cool and dissipate the gases before they leave the barrel.

A silencer is a lot like the muffler on your car (in fact, both were invented by the same guy). Screwing a silencer onto the barrel of a gun doesn't "silence" the explosive bang, it just muffles the noise. That's why folks in the gun industry call them suppressors instead of silencers.

Advertisement

The decibel level of an un-suppressed 12-gauge shotgun is 160 decibels, louder than standing on the runway when a jet is taking off (150 decibels). The Occupational Safety and Health Administration (OSHA) sets 140 decibels as the threshold of pain, although it takes far less than 140 decibels to inflict long-term hearing damage with repeated exposure.

According to a fact sheet from SilencerCo, a Utah-based silencer manufacturer, a 12-gauge shotgun equipped with a silencer registers 137 decibels and a silenced .22 rifle is muffled to 116 decibels, slightly louder than an ambulance siren. Still loud, just not eardrum-busting loud. 

That may explain why, contrary to popular belief, silencers are seldom used in criminal acts. One study looked at federal court cases involving silencers reported in the Lexis/Westlaw database between 1995 and 2005. Of the 153 cases reported, just two cases involved a silencer being used in a murder case, and overall, only 12 involved the use of a silencer in the commission of a crime. Gun control advocates, however, point out that silencers have been used in some high-profile crimes.

Advertisement