Suppressor (Fallout 4)

A suppressor is a muzzle weapon mod

Effects
The suppressor decreases the noise emitted from firing a weapon in Fallout 4, which decreases the chances of detection by nearby NPC characters. For some weapons, such as the 10mm pistol, this decreases the AP cost when used in V.A.T.S.

One drawback of suppressors is that they greatly reduce the range of projectile weapons, by 30 points. They do, however, slightly increase accuracy while considerably decreasing recoil.

Note that suppressed weapons in Fallout 4 are not completely silent, as nearby enemies will be partially alerted and go into Caution mode if they hear the suppressed gunfire (or see someone get shot). Repeated shots with the suppressed weapon will cause enemies to eventually start blind-firing in the general direction of wherever the player character fired the weapon, though repositioning can confuse them.

Locations

 * A suppressed pipe bolt-action is always in stock at Drumlin Diner early in the game. It is sold by Trudy.
 * The Deliverer is a unique 10mm pistol that comes with a suppressor by default. It is given to the Sole Survivor by Deacon during the quest Tradecraft.