guns.connect.fi/rs/index.htmlwhen thinking of a silencer, think "muffler" as that which would be on a car, in some ways the way a firearms suppressor redirects sounds while allowing the hot gasses to expand is much like that something you'd find on a car such as glass packs.
Modern suppressors use baffles that are very precisely machined to control the way the gasses are vented away from the bullet and allowed to cool, they also are very good at trapping or attenuating sound frequencies. Very little harm is done to accuracy and often times the bullets get a velocity boost as the suppressor in some ways acts as a barrel where gasses are still working to propel the bullet out the muzzle.
Older designs used "wipes" that would come in direct contact with the bullet, this changed both accuracy as well as velocity. The things also wore themselves out rather quickly.