Weapon modifications (DXHR)

In Deus Ex: Human Revolution, several different weapon modifications are available. Each one either improves one of the weapon's attributes or adds an extra feature to the weapon. Not every modification is compatible with each weapon.

Laser Targeting System
Description: Replaces reticle with red-dot aiming.

Available locations

 * Obtainable from Quest rewards for completing Lesser Evil quest.
 * Obtainable in a portable building in Highland Park (near the electrical field).
 * Purchasable from Greyson at the Gas Station (Act 4).
 * Purchasable at Hung Hua Hotel 1st Floor (Act 5).

Silencer
Description: Sound suppressor, reduces the noise made when firing a gun. Only Available for 10mm Pistol, Machine Pistol, and Combat rifle.

Available locations

 * Purchasable at from Seurat in the Detroit Apartments 2nd floor (accessible through fire escape by the basketball court).
 * Purchasable in Hung Hua Hotel 1st floor.
 * Found in a drawer in Montreal - Online News Division (Level 3).
 * Quest reward from Smash the State (Act 4) Detroit by Knocking out target "White" instead of killing him.

Ammo Capacity Upgrade
Description: Increases ammo capacity of given weapon, upgrade depends on weapon: Revolver +1, Pistol +3, Shotgun +2, Combat Rifle and Machine Pistol +10, Heavy Rifle +25.

Available locations

 * One locked behind a level 5 security door below the helipad of the Sarif building.
 * One underneath the floor in a hole in Derelict Row, in the area next to a sewer cover.
 * One behind the electronically locked door in the alley east of Sarif building, where the player could possibly meet Ezekiel Sanders.
 * Obtainable in Cloak & Daggers sidequest. (If you choose to give the crossbow and give her the option of arresting O'Malley, she will reward you with 2 Ammo Capacity Upgrades and 2000 credits)
 * Found in Tai Yong Medical's Cat walk Room 2.
 * Found in the east of Youzhao district, on a rooftop behind two boxes and a grate. A long ladder leads up to the roofop, nearby is a wall that can be punched out. A gated security door leads to this area which leads to Kuaigan District. This area is also close to the penthouse you're asked to check out in the main quest.
 * Another one also in Youzhao district west, in a secure storage room in an alley.

Reload Speed Upgrade
Description: The QuickFire Reload Kit improves the breech and feed mechanisms of most handguns, rifles, and combat firearms to decrease reloading time.

Available locations

 * FEMA Facility, Level -4, in the security office near the elevator to -5.
 * One locked behind a level 2 secured garage left of the Hung Hua Hotel's first floor.

Rate-of-Fire Upgrade
Description: The Rate Increment upgrade optimizes the trigger and firing mechanisms of most handguns, rifles, and combat firearms, thereby increasing their cyclic rate of fire.

Available locations

 * One inside The Hive's interrogation room (accessable by air vent).
 * One as a reward from the subquest with Carella (Lesser Evil, gotten at Sarif's industries)

Target-Leading System
Description: Anticipates a target's movement and shows where to shoot for a successful hit. For crossbows and tranquilizer rifles.

Available locations

 * One in a low-level locked garage west of The Hive.

Target-Seeking System
Description: Allows automatic headshots after locking on to a target by moving the reticle over the target. Only works when the reticle is not too far from the target. Only for the combat rifle.

Available locations

 * One purchasable from the merchant in Hung Hua Hotel.