Weapons Mod Workshop is a Rare key in MW4 DMZ. It opens a workshop on the second floor of the military repair garage at Chang-san Air Base. Below is where the garage is, the way up to the door and everything we found in its 14 containers.
- The workshop is on the second floor of the military repair garage at Chang-san Air Base (B5), directly west of the base clinic.
- Go in under the red banner on the south side, up the metal stairs and west to the grey metal door.
- The air base was an Extreme threat area in our run, and this part of it is full of AI.
- 14 containers with a Cipher Code Ledger, a Small Secure Backpack recipe and an Epic 2-Plate Helmet Armor Vest, at least $17,550 in loot.
- Worth it only if you are already doing Operation Iron Citadel and looting the air base. Otherwise skip the trip.
Where the Weapons Mod Workshop Is
The Weapons Mod Workshop is in the military repair garage at Chang-san Air Base, grid B5, directly west of the base clinic. The garage is a grey concrete building with a wide dark opening on its south side and a long red banner with Korean text above it. The workshop is on the second floor, behind a plain grey metal door with a small window at the west end of the upper floor. The garage is a short walk from two other key rooms on the base, the Commandant Office and the Field Depot. The air base was an Extreme threat area in our run. You can also find the door under the keys layer on our interactive MW4 DMZ map.
Click to enlarge The way into the repair garage, under the red banner. 
Click to enlarge The workshop door with the unlock prompt, brightened. 
How to Get the Weapons Mod Workshop Key
The Weapons Mod Workshop key is field loot, so it can drop from ordinary containers on Hajin. We do not know of a fixed spawn for it. Every other key and the door it opens is in our MW4 DMZ keys guide.
The Route to the Door
- Come around the south side of the garage, past the military trucks, to the wide dark opening under the red banner.
- Walk in, cross the ground floor of the garage and take the metal stairs up to the second floor.
- Head west across the dark upper floor. The grey metal door with the small window at the end is the workshop.
What Is Inside the Weapons Mod Workshop
The door opens into a short corridor with a window and then the workshop itself, a dim room with a tool wall over a workbench, long metal shelving stacked with green ammo crates and a second grey door that leads back out to the upper floor of the garage. Most of the containers sit on and under the shelving.
Click to enlarge The workshop with the tool wall and the second door, brightened. 
Containers
- 5× Military Locker
- 2× Rifle Case
- 2× Tool Box
- 1× Ammo Box
- 1× Armor Box
- 1× Cache
- 1× Equipment Case
- 1× Footlocker
The containers decide the loot. Tap one to see what it can drop in our loot data.
Loot
-
Cipher Code Ledger Epic $5,000 Rifle Case -
Small Secure Backpack Recipe Rare $5,000 Tool Box -
2-Plate Helmet Armor Vest Epic $2,500 Loose in the room -
Medium Backpack Rare $1,000 Footlocker -
APOC-338 Uncommon $1,000 Cache -
Infantry Invasion Plans Uncommon $1,000 Military Locker -
Cronen Squall Common $400 Military Locker -
MAR-9 Common $400 Rifle Case -
Disposable Parachute Rare $300 Military Locker -
Warlord Common $200 Rifle Case -
Drill Charge ×2 Uncommon $100 each Loose in the room, Military Locker -
Portable Radar Uncommon $100 Military Locker -
Trip Wire Uncommon $100 Equipment Case -
Claymore Common $50 Military Locker -
Concussion Grenade Common $50 Military Locker -
Frag Grenade Common $50 Loose in the room -
Proximity Mine Common $50 Equipment Case -
Snapshot Grenade Common $50 Equipment Case -
Thermite Common $50 Equipment Case -
Zip Gun Common $50 Loose in the room -
Ammo Pack ×4 Common Rifle Case, Cache, Military Locker, Ammo Box -
Armor Plate ×7 Common Tool Box, Footlocker, Military Locker, Armor Box -
Metals ×8 Tool Box -
Synthetics ×7 Footlocker
From one opening in our own run. Loot is random, so your room can roll differently, and we add every new run of this key. Values are per item, from the in-game tooltips. The loot value adds up every item with a known value and the cash, so it is a lower bound: crafting resources and items without a value are not in it.
The best finds were two $5,000 items. One rifle case held a Cipher Code Ledger next to a Common Warlord, and the tool box on the workbench held a Small Secure Backpack recipe and an armor plate. An Epic 2-Plate Helmet Armor Vest ($2,500) lay loose on the same workbench. The five military lockers gave a Common Cronen Squall, Infantry Invasion Plans ($1,000), a Disposable Parachute, a Portable Radar, a Concussion Grenade, a Drill Charge, a Claymore and two armor plates. The long case on the shelving that the game calls a Cache held an Uncommon APOC-338, and the second rifle case a Common MAR-9. The footlocker had a Medium Backpack, the equipment case four lethals and tacticals, and the armor box, the ammo box and a red tool box gave plates, ammo and Metals. A Drill Charge, a Frag Grenade and a Zip Gun lay loose on the shelves. Despite the name, the guns were only Common and Uncommon. Counting only items with a known value, the loot in the room was worth at least $17,550.
Click to enlarge The Cipher Code Ledger in one of the rifle cases. 
Click to enlarge The Small Secure Backpack recipe in the tool box on the workbench. 
Is the Weapons Mod Workshop Key Worth It?
Only if you are already doing Operation Iron Citadel and looting the air base anyway. Then it is a good extra stop. Otherwise we would not travel all the way to the air base for this key. The air base is dangerous and the loot is only okay. In our run most of the value sat in two $5,000 items and an Epic vest, and the guns were Common and Uncommon. Be warned that there are a lot of AI enemies in this part of the air base, and AI with riot shields can push into the workshop while you loot, so keep an eye on both doors.
Frequently Asked Questions
Where is the Weapons Mod Workshop in MW4 DMZ?
At Chang-san Air Base, grid B5, on the second floor of the military repair garage directly west of the base clinic. Go in through the wide dark opening under the red banner on the south side of the garage, take the metal stairs up and walk west across the upper floor to the grey metal door.
Where do you get the Weapons Mod Workshop key?
It is field loot, so it can drop from ordinary containers on Hajin. We do not know of a fixed spawn for it.
What is inside the Weapons Mod Workshop?
We counted 14 containers, five military lockers, two rifle cases, two tool boxes, a cache, a footlocker, an equipment case, an armor box and an ammo box. Ours held a Cipher Code Ledger and a Small Secure Backpack recipe worth $5,000 each and an Epic 2-Plate Helmet Armor Vest, with the loot worth at least $17,550. Despite the name, the guns were only Common and Uncommon.
Is the Weapons Mod Workshop key worth it?
Only if you are already doing Operation Iron Citadel and looting the air base. Otherwise it is not worth the trip, because the air base is dangerous, this part of it has a lot of AI enemies and the loot is only okay.
