To open the Chang-san Air Base Armory in Modern Warfare 4 DMZ, deploy on the Tier 2 Story Mission Operation Iron Citadel, upgrade its Multi-Use Access Card in Admin Complex No. 2, then use the resulting single-use Armory Keycard and a six-digit code made from three Transfer Slips found during that deployment. The vault is in the underground bunker at Tac-Map B5–B6; it is guarded by Commander Colossus. DMZ has no free multiplayer-style respawn: if your Operator is not recovered in the raid, they go MIA, and unprotected backpack loot is lost.
The instructions below reflect launch-week player guides and official material available through October 29, 2026. The game entered Early Access on October 20 and launched October 23, 2026; room loot, key labels, and MIA rescue costs may change in updates.
Where is the Chang-san Air Base Armory?
The Armory is underground at Chang-san Air Base in western Hajin, North Korea, around Tac-Map grid B5–B6. Enter the bunker through the south-side Entrance Garage or a bunker entrance inside the base; the vault itself has red trim, an “OFFICERS ONLY” sign, a keypad marked “ENTER ACCESS CODE,” and a card reader that says “Requires Air Base Armory Access Card.”
Call of Duty’s October 2026 threat labels rate the Air Base Exterior Critical and the Air Base Bunker Extreme. The base sits against a massive granite hillside, with an underground complex larger than the surface footprint, according to the official October 5 description. Plan for a dangerous AI encounter even if the mission’s spawn arrangement keeps rival squads away from the immediate mission zone.
How do I enter the Air Base Armory in MW4 DMZ?
For a first clear, the reliable entry route is Operation Iron Citadel. You need both the upgraded Air Base Armory Card – Single Use and the current deployment’s six-digit code; neither one opens the vault by itself.
Before you deploy
Iron Citadel is a Tier 2 Story Mission. First complete the Tier 1 stories Critical Extraction, Silent Ledger, and Shopping Hacks, then select Iron Citadel from the Deploy screen. Its mission card recommends a 3-Plate Armor Vest, Medkit, and Ammo Box and lists the threat as Critical. A suppressed primary and extra plates are sensible choices for the AI-heavy route. If you already own an Air Base DRC Weapons Locker key and want the extra locker, move it from your Stash into a protected slot before deploying.
Mission guides report that Iron Citadel spawns the squad outside Chang-san with objective markers and isolates the mission zone from rival-squad spawns. That is not a PvP-off setting: other Operators may still be a concern, and the garrison remains dangerous. GamingProMax reports that a first-clear Armory visit cannot bypass this mission path.
Find and upgrade the access card
- Approach the base carefully. The mission route suggests crouching through a gap in the south perimeter wall and clearing the guard tower first. Follow the objective markers rather than crossing the exposed surface area without a plan.
- Search the four marked buildings. Look for an Air Base Access Card – Multi Use, an Epic item. The mission scans buildings, not a single fixed container: player guides report possible locations such as a warehouse or vehicle shed, an office, or a tiled washroom. A small safe on a metal cabinet is one reported spot. The HUD shows “SCANNING FOR ACCESS CARD,” followed by either “SCAN RESULT: KEYCARD FOUND” or “SCAN RESULT: NO KEYCARD FOUND.” Search all four zones if needed; picking up the card can raise the threat to Extreme.
- Go to Admin Complex No. 2 and enter the upstairs Server Room. The door requires the Multi-Use card. Inside, start AIRBASE ACCESS CARD – UPGRADE and defend the room while enemies push in.
- Take the finished card. When the upgrade completes, interact with TAKE ARMORY ACCESS CARD and confirm the HUD says ACCESS CARD UPGRADED. Leaving the room without collecting the result stalls the objective. The upgrade triggers the base alarm and raises the threat to Extreme; an enemy helicopter may bring reinforcements outside Admin Complex No. 2.
- Reach the bunker and gather the code. From the bottom of the Server Room stairs, a door on the left leads toward the bunker without requiring a return across the entire surface base. The south Entrance Garage is another route.
- Open the vault with both credentials. Assemble the six-digit code from the three Transfer Slips, enter it on the keypad, then swipe the upgraded single-use card at the reader on the right.
AllThingsHow records 14 Iron Citadel HUD objectives, from approaching and infiltrating the base through finding the card, upgrading it, collecting the code, exploring the Armory, collecting the Manifest, planting explosives, capturing the SAM site, and exfiltrating with the Manifest. The objectives make the mission longer than simply opening the vault: the extraction objective is part of the run.
What is the Air Base Armory code? Does it change every match?
There is no universal code. The vault uses a six-digit code assembled from three two-digit fragments on documents titled TRANSFER SLIP – DO NOT FILE. Each slip is labeled First, Second, or Third Segment. The fragments change every deployment, while the note rooms are reported to stay in the same general locations.
Collect all three and follow the labels, not the order you picked them up. The HUD’s Known Digits counter should reach 3/3 before you try the keypad. A guide example recorded fragments 71, 75, and 66 as 717566; that is only an example from one match, not a code to reuse. Campaign “Stranded” bunker codes and codes shown in videos from other runs will not work for your deployment. The requirement is six digits; a guide claiming a three-digit code conflicts with the other walkthroughs.
Where should I look for the Transfer Slips?
Guides use different names for the same likely rooms, so search by room function and the in-game slip label rather than relying on one guide’s room name. The reported search areas are:
- Medical or recovery area: a Recovery Room reception desk in some guides; a Medical Wing laboratory desk in others.
- Administrative area: the Dining Room east of the Administrative Wing, or the Administration Conference Room central table.
- Security or control area: downstairs in the Security Wing, or in the Control Room near workstations.
AllThingsHow quotes the in-match Transfer Slip wording and Known Digits counter, making those HUD clues more dependable than a copied static code or a disputed room label. If the HUD says 2/3, keep checking the remaining area rather than guessing the last pair.
Air Base Access Card vs Armory Keycard vs DRC Locker key
These are separate items with separate jobs. The ordinary Multi-Use card unlocks restricted base doors and the Server Room; only the upgraded single-use card opens the Armory vault, and the DRC key opens one additional weapons locker inside it.
| Key | Rarity and grid | What it opens | How to get it | Uses and storage |
|---|---|---|---|---|
| Air Base Access Card – Multi Use | Epic, B5 | Restricted doors around the base, including the Admin Complex No. 2 Server Room | Search mission-marked buildings during Iron Citadel | Multi-use; the mission card is upgraded, not used directly on the vault |
| Airbase Armory Keycard – Single Use | Legendary, B5 | Armory vault, together with the six-digit code | Upgrade the mission card in the Server Room | One use; created during the mission, not a reusable key to bring from Stash |
| Air Base DRC Weapons Locker | Ultra, B6 | One DRC Weapons Locker inside the Armory | World loot or containers; can be brought from Stash | One locker; bring in a Secure Slot if you want to protect it on a failed run |
| Supreme Leader’s Bunker Access Card | Legendary, B6 | Supreme Leader’s Bunker deeper in the same bunker complex | Reported Iron Citadel completion reward or Bale drop | Single-use; it does not open the Armory vault |
The exact card label varies slightly between guides: the completed mission item is also called the Air Base Armory Card or Airbase Armory Keycard. Its reported item text is “Unlocks Armory in Chang-san Air Base in North Korea.” The distinction that matters at the vault is that it is the upgraded, one-use card—not the ordinary Multi-Use card.
Two other keys sometimes confused with the Armory items are the Epic Commandant Office key for the second floor of Admin Complex No. 2, and the Weapons Mod Workshop key for the military repair garage west of the clinic. A Field Depot key opens the B5 Field Depot door. These are separate destinations, not alternate Armory credentials.
Why does the vault say “NO AIRBASE ARMORY ACCESS CARD IN INVENTORY”?
This message usually means the required upgraded, single-use Armory card is missing. Having the Multi-Use Access Card or the DRC Weapons Locker key does not satisfy the vault reader.
- Check the Server Room objective: did you start the upgrade and wait for it to finish?
- Confirm you interacted with TAKE ARMORY ACCESS CARD and saw ACCESS CARD UPGRADED.
- Make sure the card is still in your inventory; if already consumed on an earlier attempt, you need another entry method.
- Do not confuse the keypad code with the card. The code does not replace the card, and the card does not replace the code.
What is inside the Chang-san Air Base Armory?
The room’s precise loot table is not officially published. Player guides describe multiple Gun Lockers—often six or more on successful runs—plus caches, cases, high-tier gear, weapons, and the mission-critical Armory Manifest; contents vary between deployments.
| Container or item | Why it matters | What is established |
|---|---|---|
| Gun Lockers | Weapons, blueprints, and 3D Printer recipes | Guide consensus says six or more may appear; no official count or drop rate |
| Ordnance or munitions crates | Targets for the plant-explosives mission objective | Mission walkthroughs mark them with yellow bomb symbols |
| Lockers, caches, and cases | Potential high-tier gear, armor plates, and weapons | Player-guide reports; contents vary |
| Armory Manifest | Required Iron Citadel mission item | Collect it and keep it until exfil |
| Air Base DRC Weapons Locker | Extra Elite locker for a DRC key holder | Its position inside the Armory can move each deployment |
Examples are not promises. AllThingsHow recorded a green weapons locker containing a KG-7 Vulcan, an Epic sniper, and 8,500 DMZ Cash in one match. ConquestCapped reported a Launcher Weapon Manual and gold PPSh from one squad run. Neither example establishes a guaranteed drop. A sealed chamber with a tank has also been mentioned by a player report, but the report says players had not found the parts to activate it; treat it as unconfirmed.
After taking the Manifest, plant explosives on the marked crates in the Armory, then on the three strike aircraft: one in the hangar and two outside. Capture the SAM site, then board the exfil chopper by the base fence with the Manifest still in inventory. The Story Mission item slot is intended for mission objects; avoid replacing or dropping the Manifest while looting.
One AllThingsHow completion recorded a Story Mission Payout of 5,000, three Side Ops payouts totaling 1,500, and 1,150 cash banked, for 7,650 banked cash in that run. The same walkthrough reports a mission-select card listing an LTV and 25,000, while later guides identify the completion key as the Supreme Leader’s Bunker Access Card. These are one-run and guide-reported rewards, not a guaranteed payout schedule.
How do I beat Colossus at the air base?
Commander Colossus is an armored, minigun-wielding boss. Player guides recommend using cover and a scoped rifle or other sustained fire from the corridor doorway or metal staircase; they warn that grenades and explosives do no damage to him.
He may patrol the Entrance Garage, the wilderness approach, or the far end of the bunker corridor, so listen and check the route before pushing into the vault area. AllThingsHow describes peeking the corridor doorframe to take head shots, then reloading in cover. Other guides describe a prone position left of the doorway, firing at his shoulder while the frame blocks return fire. These are player-reported tactics, not an official boss vulnerability guide; avoid standing in the open against the minigun.
GamingProMax reports that depleted-uranium rounds are effective, that toxic green gas can fill the Armory floor, and that a $50,000 bounty appears on the FOB Boss Board. AllThingsHow recorded the elimination banner “ELIMINATED ARMORED COMMANDER” and 1,198 XP. The same source reports Military Composites as a Colossus drop for the 3D Printer. There is no published official figure for his health, exact spawn rate, or whether he respawns after being killed in the same deployment.
What happens when you die in MW4 DMZ?
DMZ is an extraction mode, not a multiplayer match with a free return to the same raid. A teammate can revive a downed Operator, but once an Operator is eliminated and not recovered in the raid, that deployment is over and the Operator becomes Missing in Action (MIA).
| Outcome or protection | What it keeps | What it does not keep |
|---|---|---|
| Successful exfil | Your equipped loadout and backpack contents you extract with | Nothing you leave behind in the raid |
| Secure Slot | Selected eligible backpack items return to the FOB Stash after death | It does not protect every backpack slot; weapons do not fit |
| Weapon Insurance Contract | Equipped weapons held on death return to the Stash, according to the in-game text quoted by DMZMap | Backpack loot or the Operator |
| Operator Rescue Beacon or paid MIA rescue | Operator traits and Dog Tag rank when rescued | Gear or backpack contents |
On a failed run, you lose the loadout, backpack, and cash picked up during that match. You keep DMZ XP, Weapon XP, camo progress, Stash, and Bank; Activision and Infinity Ward say death does not impose an XP penalty. Secure Slot items are the exception for eligible carried loot: recipes and Weapon Manuals can fit, but weapons cannot. VGKami lists the Medium Backpack as the first practical craftable bag with Secure Slots, with a reported crafting cost of 50 Synthetics and 5 Rigid Synthetics.
A key in an ordinary backpack slot is lost to you if you die, though ConquestCapped reports another Operator may loot it from your body. Keys successfully extracted go to Stash, but a stored key does nothing until moved into a loadout; keys do not stack. A Secure Slot is therefore useful for a DRC key you bring in, while the Armory card itself is generated by the mission rather than carried in as a reusable stash key.
MIA rescue costs DMZ Cash from the Bank at the Operators station, with a cost that scales by Trait Points; the exact formula is not published here. A rescued Operator returns without gear but keeps Traits and Dog Tag rank. Dismissing an MIA Operator resets Dog Tag progress (reported as Steel I) but not Stash or DMZ level, and MIA Operators do not expire. A Rescue Beacon skips the cash rescue fee; it does not recover backpack loot.
Does my key or Manifest survive if I die?
A key or Manifest in an ordinary backpack slot is not protected by the fact that it is a mission run. The Secure Slot protects selected eligible items, while the Story Mission item slot is the safer place for mission objects such as the Manifest.
- DRC key: Put it in a Secure Slot before the Colossus fight if you want it back after a wipe. If it is in a normal slot, death can cost you the key.
- Manifest: Keep it in the mission-item slot, or another protected slot if eligible, and do not discard it while looting. Iron Citadel calls for exfil with the Manifest.
- Armory card: It is single-use and produced during Iron Citadel. Once spent, you cannot use that card for another vault opening.
- Disconnect: Disconnect is distinct from death. Infinity Ward says reconnection is possible while the same server is running. After a reported October 21 Early Access disconnect bug, Activision said affected players retained starting equipment and progression but lost that match’s loot; there is no verified guarantee that every secured item survives every disconnect.
How do I get back into the Armory?
After the single-use card has opened the vault, there are two reported ways to enter again: run Operation Iron Citadel again to generate another mission card, or spend an Ultra Door Breacher Charge on the used door. MW4 has no skeleton key, and the Breacher Charge does not work on every door, so reserve it for a room you cannot reopen another way. ConquestCapped also cites the charge for a second visit to the Supreme Leader’s Bunker.
The code is deployment-specific, so a return run requires collecting that run’s Transfer Slips again. The DRC locker’s location can also shift inside the Armory between deployments. The available guides do not establish whether an already-open vault stays open after the squad wipes; plan as though you will need another entry method.
What should I prioritize during the run?
- Unlock Iron Citadel, deploy with armor and healing supplies, and secure the Multi-Use card from the four marked search zones.
- Upgrade it upstairs in the Server Room at Admin Complex No. 2, take the finished Armory card, and use the nearby bunker route if it is safer than crossing the base.
- Collect the Transfer Slips until Known Digits reads 3/3; enter the six-digit combination and swipe the single-use card.
- Deal with Colossus from cover. Take the Manifest before optional containers, then check Gun Lockers and the DRC locker if you brought its key.
- Complete the explosives, aircraft, and SAM objectives. Exfil with the Manifest and any loot you intend to keep.
Keyed rooms elsewhere in DMZ are reported by ConquestCapped to grant 300 XP per opening, while keys sell for about 100 DMZ Cash. Those figures make using a relevant key generally more valuable than selling it, but they are guide-reported values rather than official fixed rates. The three buildings inside Chang-san Air Base are also ranked among Hajin’s better loot stops by an MW4Meta route citing MrDalekJD’s October 23, 2026 run; that is a route ranking, not an official drop-rate guarantee.
Frequently Asked Questions
How much is the Colossus bounty in MW4 DMZ?
GamingProMax reports a $50,000 bounty listed on the FOB Boss Board. Treat that as a guide-reported figure rather than an official, guaranteed payout.
How much XP does defeating Colossus give?
AllThingsHow recorded 1,198 XP alongside the “ELIMINATED ARMORED COMMANDER” banner in one run. No official fixed XP award is published in the available information.
What crafting material can Colossus drop?
GamingProMax reports that Colossus can drop Military Composites for the 3D Printer. Drop contents may vary, so this should not be treated as a guaranteed reward.