User blog comment:PFC Arkalis/Battleblog 8: Build your weapon of choice/@comment-187.158.186.193-20110826230658/@comment-1990578-20110828025229

Suppressors trap the gases coming out from the end of the barrel to reduce muzzle flash, but to use them, operators use special sub-sonic rounds so that they don't destroy the suppressor. Using regular rounds would degrade the suppressor much faster because of the round's speed.