Do suppressors on sniper rifles work?

Suppressors are often thought to work like magical devices that make guns almost inaudible. That is not the case. While a suppressor can reduce the sound almost by a good fraction if the sniper is close to an enemy the suppressor won't matter since sniper rifles are extremely loud guns.

It also decreases the range of bullet. A suppressor is effective on a sniper if the target is a mile away.