Silencers, Suppressors, and Cans: Oh my! What’s the difference? Nothing really; all of the names refer to the same item.
Silencer is the name used by Congress to designate a device for “silencing, muffling, or diminishing the report of a portable firearm, including any combination of parts, designed or redesigned, and intended for use in assembling or fabricating a firearm silencer or firearm muffler, and any part intended only for use in such assembly or fabrication.” 18 USC § 921(a)(24). It is worth noting that Congress also used the term “muffler,” but this has never caught on.
The factual truth is silencers do not make a gun silent. The item merely suppresses the noise made by the burning of powder. There is no effect on the sonic crack caused by supersonic bullets, and even the boom caused by burning powder cannot be completely contained. Because a ‘silencer’ only suppresses sound, the industry properly refers to these items as ‘suppressors.’
To further complicate matters, the term ‘can’ has entered American slang as a name for a suppressor or silencer. The name comes from the shape of the device and leaves the functionality unstated. If you start looking for a suppressor, you’re bound to hear someone use this term when discussing various suppressors.
Regardless of what you call it, a NFA silencer suppresses the sound signature of a firearm without eliminating it. A suppressor is more effective on some guns than others, but in no case is a firearm ever truly silent. (However, when all you hear is the hammer falling and a rush of air you’ll be close enough.) There aren’t three types of devices, only three names for the same device; so when you go out shopping for a ‘silencer’ don’t be afraid to buy a ‘suppressor’ or ‘can!’