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.

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

 * Inside the locker room near the Morgue in the Police Station
 * On the highest level of the fire escape just within Derelict Row (requires object stacking or Leg Prothesis augmentation to jump up broken stairs)
 * 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.
 * Where you find the eBook Better Than Nature in Tai Young Medical
 * Inside a locker within a locked office of the Picus Sub-Basement.

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). On PC version in 5 test runs Laser targeting system was rewarded instead of this. Need recheck. This is not available on the xbox 360 version
 * Purchasable from Pen Xin Had from Alice Garden Pods.
 * Found behind a breakable wall on the 3rd floor of Alice Garden Pods.
 * One inside a men's room stall at Picus TV.
 * One inside Detroit Police Station armory, behind locked door.
 * Hidden above Pen Xin Had inside Alice Garden Pods. Need to stack alot of boxes to get to it.

Damage Upgrade
Description: Increases weapon damage.

Available locations

 * In THE VERY first mission (Sarif Plant) in Lab 2, in Storage room 3 on bottom of an open crate near guard.
 * Purchasable from Grayson at the Gas Station during both visits.
 * Purchasable from the merchant in Hung Hua Hotel (Lin Fu Ren).
 * in the bottom level of the Harvester Hideout in one of the cells with a breakable wall.

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, Laser rifle +100.

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)
 * FEMA Facility, In first guarded hangar, in small security building with a guard and openable window.
 * 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.
 * Behind a breakable wall in the passageway after confronting Isaias Sandoval.
 * Found in Panchea, in the first building (has a large robot in the middle). Go up the stairs heading towards the "M1" Marker. It's in this same corridor as the M1 Marker (Elevator). From the stairs, facing the M1 Marker / Elevator, it is on the left about half way down the corridor on top of the very highest scaffolding, on top of a box with a sniper rifle. Up stairs--25 meters from M1 elevator marker--left side of corridor--top of scaffolding on a crate w/a sniper rifle... Easy Peasy

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 Grayson 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. Available for 10mm Pistol, Machine Pistol, and Combat rifle.

Available locations

 * Purchasable at from Seurat in the Detroit Downtown 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.

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

 * Can be bought from Gang leader near helipad in FEMA facility.
 * One in a low-level locked garage west of The Hive.
 * Purchasable from Grayson at the Gas Station after your return to Detroit.
 * Purchasable from Seurat after your return to Detroit.

Armor Piercing System
Description: Negates enemies armor bonuses effectivley doing more damage.

Avaliable Locations

 * One can be found in Jensen's apartment in his secret stash behind the TV. Type the code obtained from his personal computer into the security panel on the wall to open.
 * Purchasable from Grayson at the Gas Station after your return to Detroit.
 * Located in the Alice Garden Pods under the south side stairs.

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. Avaiable for the combat rifle and machine pistol.

Available locations

 * One purchasable from the merchant in Hung Hua Hotel.
 * Purchasable from Seurat after your return to Detroit.

Cooling System
Description: Prevents rapid overheating of weapon during constant fire. Avaiable for plasma and heavy rifles.

Available locations

 * Inside the armory of the Picus Sub-Basement.
 * Purchasable from Grayson at the Gas Station after your return to Detroit.

Burst Round System
Description: Fires two cartridges per shot, doubling the damage. Only for shotgun.

Available locations

 * Purchasable from Grayson at the Gas Station.

Explosive Rounds
Description: Allows the revolver to fire explosive rounds, increasing damage.

Available locations

 * Purchasable from Pen Xin Had from Alice Garden Pods.
 * Purchasable from Grayson at the Gas Station after your return to Detroit.

Heat Targeting System
Description: Allows the rocket launcher missiles to home onto targets via heat-seeking.

Available locations

 * Tai Yong Medical, in a safe in Zhao's office (Hacking 5 required, or passcode from pocket secretary in room prior)
 * Purchasable from Seurat after your return to Detroit.