Since there were a number of questions regarding silencers on the boards recently, I though it would be entertaining and educational to post this video.
The rifle depicted is of the same type (Macmillan Tac-50) used for the 2450(ish) meter kill in Afghanistan in 2002. Note that there is no kickup of dust in front of the muzzle, as one would expect from a 12.7mm cartridge and 750gr bullet. Since the silencer acts effectively as a barrel extention, the velocity and effective range of the bullet is further increased. Compare the sound of the rifle with the 7.62mm firing in the background.