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 all modifications are compatible with every weapon.

Weapon/modification combinations
Aside from "Ammo Rounds (base / upg)" and "Note / Special upgrade" then each column referers to a general upgrade. Numbers in these cells means base / max upgrade possible. Slash hyphen, "/ -", means no upgrade possible.

Example: "2 / 5" means a base value of 2 with a maximum of 5, hence 3 upgrades can be added. Note: Laser modification is known to cause less accuracy (you need to aim higher than where the dot shows to hit) when in zoom/alt mode on both sniper rifles. May apply to other weapons too.

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 Detroit Police Station armory, behind locked door.
 * One inside The Hive's interrogation room (accessible by air vent).
 * Purchasable from Peng Xin Hao in Alice Garden Pods.
 * Hidden above Peng Xin Hao inside Alice Garden Pods (reachable by stacking boxes, breaking the weak wall in section 04, or through use of the jump enhancement).
 * One inside a men's room stall at Picus TV.
 * Can be bought from Seurat, during the second visit to Detroit.
 * Belltower dock, locked room on the left sublevel of the outside area, rooms are guarded by a ceiling mounted turret.

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 Detroit Police Station.
 * On the highest level of the fire escape in the entrance area to Derelict Row. Can be obtained by object stacking, reaching for it after jumping or using the jump enhancement augmentation.
 * FEMA camp, 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 Yong Medical.
 * Inside a locker within a locked office of the Picus Sub-Basement.
 * Can be bought from Grayson during your second visit to Detroit.
 * Purchasable from Lu Pin Rong in the sewers beneath Belltower dock.
 * Belltower dock, upper area of warehouse interior on a shelf.
 * In Singapore, inside the soldier barracks, behind a locked room. This is located in the same building as the jamming relay control panel. The code is 1385.

Damage Upgrade
Description: Increases weapon damage. Available locations
 * At the Milwaukee Junction plant in Lab 2, in Storage room 3, inside a crate that a Purity First member is searching.
 * Purchasable from Grayson at the Gas Station during both visits.
 * Purchasable from Lin Fu Ren in Hung Hua Hotel.
 * Harvester Hideout, bottom level, in one of the cells with a breakable wall.
 * Belltower dock, locked room on the left sublevel of the outside area, rooms are guarded by a ceiling mounted turret.
 * Omega Ranch, in the room where you disable the jammer, behind a level 5 security door.

Ammo Capacity Upgrade
Description: Increases ammo capacity of given weapon, upgrade depends on weapon: Revolver and Sniper Rifle +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. This can easily be found during Cloak & Daggers sidequest.
 * 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 Jenny Alexander the crossbow and accept the option of arresting O'Malley. She will reward you with 1 Ammo Capacity Upgrade and 2000 credits.
 * FEMA camp, the warehouse with the elevator to the lower levels, in the small security building with a guard and openable window.
 * 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.
 * Found in Singapore as soon as you wake up. You can enter the small building in the first area through a vent on the roof or my hacking the door.
 * Found in Tai Yong Medical's Cat walk Room 2.
 * Behind the fenced in area on the Picus helipad, reachable through a breakable wall, hackable gate, or use of the jump enhancement.
 * Behind a breakable wall on the helipad of the Chiron Building right after returning to Detroit.
 * Can be bought from Grayson during second visit to Detroit.
 * Behind a breakable wall in the passageway after confronting Isaias Sandoval.
 * In the Harvester Hideout, in a Level 5 safe in the living quarters area outside of Tong's office. You can find the code in a pocket secretary on one of the guard's or use an autohack device, if needed.
 * Purchasable from Lu Pin Rong in the sewers beneath Belltower dock.
 * At the Omega Ranch, in a level five locked storage room, just off of the starting area (also accessible through a vent on the roof).
 * Found at Panchaea, in the first building. Go up the stairs heading towards the Elevator. From the stairs, facing the 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.

Laser Targeting System
Description: Replaces reticle with red-dot aiming. Available for 10mm Pistol, Revolver, Machine Pistol, Combat Rifle, Sniper Rifle, and Heavy Rifle. 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 during second visit.
 * Purchasable from Lin Fu Ren in Hung Hua Hotel, during both visits to Hengsha.

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 during first visit to Detroit.
 * Purchasable from Lin Fu Ren in Hung Hua Hotel, during both visits to Hengsha.
 * Found in a drawer in Montreal - Picus Online News Division (Level 3, Broadcast Room, in front of the turret).
 * Quest reward from Smash the State sidequest during the second visit to Detroit. Obtained by knocking out Jacob 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 Highland Park.
 * 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.
 * Purchasable from Lin Fu Ren in Hung Hua Hotel, during second visit to Hengsha.
 * Belltower dock, You can find one in an open metal cargo pod located on top of a bunc of stacked metal cargo pods. May need enhanced jump to reach.

Armor Piercing System
Description: Negates enemies' armor bonuses effectively doing more damage. Exclusive upgrade for the 10mm Pistol.

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 near the kitchen 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.
 * Purchasable from Peng Xin Hao in Youzhao district during second visit to Hengsha.

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. Available for the combat rifle and machine pistol. It also has the extremely helpful ability to allow a weapon to accurately target enemies from behind cover witout exposing the user to enemy fire, even while blindfiring. Available locations
 * Purchasable from Lin Fu Ren in Hung Hua Hotel, during both visits to Hengsha.
 * Purchasable from Seurat after your return to Detroit.
 * Purchasable from Peng Xin Hao in Youzhao district during second visit to Hengsha.
 * Purchasable from Lu Pin Rong in the sewers beneath Belltower dock.
 * In Singapore, Once you've uploaded the virus to the security terminal, you can enter the restricted area. The first door before the elevator, go inside and the upgrade is atop the lockers.

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

NOTE: In the current PC version, overheating does not occur with the plasma rifle, making this upgrade unnecessary for that weapon. Available locations
 * Inside the armory of the Picus Sub-Basement.
 * Purchasable from Grayson at the Gas Station after your return to Detroit.
 * Inside the Harvester Hideout, You can find a cooling system within a Level 5 Safe. It is on the same floor where a hackable stairway and elvator door are right next to each other.
 * Purchasable from Lin Fu Ren in Hung Hua Hotel, during second visit to Hengsha.
 * Purchasable from Lu Pin Rong in the sewers beneath Belltower dock.
 * Inside Omega Ranch Hangar 18, in a secret room behind a box, near the doors that Sarif Industries scientists use to enter.
 * At Panchaea, inside one of the rooms, along with a Heavy rifle. The room has a broken door and large cart in front of it, and can only be accessed via ventshaft.

Burst Round System
Description: Fires two cartridges per shot, doubling the damage. Only for shotgun. Available locations
 * One locked behind a level 5 security door below the helipad of the Sarif building, during the second visit to Detroit.
 * Purchasable from Grayson at the Gas Station.
 * Lower Hengsha, lv 3 map, most right side of the map, there is a balcony next to stairs going downwards. On that balcony lies this upgrade.
 * Purchasable from Peng Xin Hao in Youzhao district during second visit to Hengsha.
 * At Panchaea starting area. Facing the entrance to the installation, the upgrade is hidden in one of the large metal containers on the left. It can be identified by one part of the door lying on the ground before it. Jump enhancement or a crate is required to reach it.

Explosive Rounds
Description: Allows the revolver to fire explosive rounds, increasing damage and adding splash. Available locations
 * Purchasable from Peng Xin Hao in Alice Garden Pods.
 * Purchasable from Grayson at the Gas Station after your return to Detroit.
 * Purchasable from Peng Xin Hao in Youzhao district during second visit to Hengsha.

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.
 * Purchasable from Lin Fu Ren in Hung Hua Hotel, during second visit to Hengsha.

Detroit

 * 1) Inside the factory, first mission. Lab 2, storage 3 - Damage
 * 2) Inside the police station armory - Rate of Fire
 * 3) Locker near the police morgue - Reload Speed
 * 4) Helipad storage at Sarif HQ - Ammo capacity
 * 5) Alley east and near Sarif HQ - Ammo capacity
 * 6) Underneath the floor in a hole in Derelict Row, in the area next to a sewer cover. This can easily be found during Cloak & Daggers sidequest.- Ammo Capacity
 * 7) Possible reward for Cloak & Daggers sidequest when crossbow is given up - Ammo Capacity
 * 8) Quest reward for completing Lesser Evil quest - Laser sight
 * 9) Gang Leader near Highland park - Target Leading system
 * 10) FEMA camp, ground level, first little trailer outside the main building - Laser sight
 * 11) FEMA camp, Level -4, in the security office near the elevator to Level -5 - Reload Speed
 * 12) FEMA camp, the warehouse with the elevator to the lower levels, in the small security building with a guard and openable window - Ammo capacity
 * 13) First visit to Seurat - Silencer
 * 14) First visit to Grayson - Burst Round System, Damage upgrade
 * 15) Second visit to Seurat - Rate of Fire, Target Leading system, Target Seeking System, Heat Seeking system
 * 16) Second visit to Grayson - Explosive Rounds, Cooling system, Armor Piercing system, Target leading system, Laser sight, Ammo Capacity, Damage Upgrade, Reload Speed
 * 17) Quest reward from Smash the State sidequest during the second visit to Detroit. Obtained by knocking out Jacob White instead of killing him. - Silencer

Hengsha
1. One inside The Hive's interrogation room (accessible by air vent). - Rate-of-Fire

2. Purchasable from Peng Xin Hao in Alice Garden Pods. - Rate-of-Fire

3.Hidden above Peng Xin Hao inside Alice Garden Pods (reachable by stacking boxes, breaking the weak wall in section 04, or through use of the jump enhancement). - Rate-of-Fire

4. One locked behind a level 2 secured garage left of the Hung Hua Hotel's first floor. - Reload Speed

5. Where you find the eBook Better Than Nature in Tai Yong Medical. - Reload Speed

6. Purchasable from Lin Fu Ren in Hung Hua Hotel. - Damage

7. Harvester Hideout, bottom level, in one of the cells with a breakable wall. - Damage

8. 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. - Ammo

9. Another one also in Youzhao district west, in a secure storage room in an alley. - Ammo

10. In the Harvester Hideout, in a Level 5 safe in the living quarters area outside of Tong's office. You can find the code in a pocket secretary on one of the guard's or use an autohack device, if needed - Ammo

11. Found in Tai Yong Medical's Cat walk Room 2. - Ammo

12. Purchasable from Lin Fu Ren in Hung Hua Hotel, during both visits to Hengsha. - Laser

13. Purchasable from Lin Fu Ren in Hung Hua Hotel, during both visits to Hengsha. - Silencer

14. One in a low-level locked garage west of The Hive. - Targer Leading

15. Purchasable from Lin Fu Ren in Hung Hua Hotel, during second visit to Hengsha. - Target Leading

16. Located in the Alice Garden Pods under the south side stairs. - Armour Peircing 

17. Purchasable from Peng Xin Hao in Youzhao district during second visit to Hengsha. - Armour Peircing

18. Purchasable from Lin Fu Ren in Hung Hua Hotel, during both visits to Hengsha. - Target Seeking

19. Purchasable from Peng Xin Hao in Youzhao district during second visit to Hengsha. - Target Seeking

20. Purchasable from Lin Fu Ren in Hung Hua Hotel, during second visit to Hengsha. - Cooling System

21. Lower Hengsha, lv 3 map, most right side of the map, there is a balcony next to stairs going downwards. On that balcony lies this upgrade. - Burst round

22. Purchasable from Peng Xin Hao in Youzhao district during second visit to Hengsha. - Burst round

23. Purchasable from Peng Xin Hao in Alice Garden Pods. - Explosive Rounds

24. Purchasable from Peng Xin Hao in Youzhao district during second visit to Hengsha - Explosive rounds

25. Tai Yong Medical, in a safe in Zhao's office (Hacking 5 required, or passcode from pocket secretary in room prior) - Heat Targeting

26. Purchasable from Lin Fu Ren in Hung Hua Hotel, during second visit to Hengsha. - Heat Targeting