The weapon is only available to unlock in the new DMZ mode.
With the introduction of Season 01 for Call of Duty's latest release, Modern Warfare 2. Infinity Ward made one of the new additions only available to unlock in the brand-new DMZ mode.
What is DMZ?
Only 66 players can play in DMZ mode at any one time. The map becomes more populated with AI enemies for players to take out during the playtime of the mode.
The gameplay loop in DMZ is incredibly similar to Escape From Tarkov. It involves infiltrating, completing missions of varying difficulty and then exfiltrating with anything acquired along the way.
All items found in DMZ can be kept for future runs in the mode, and that's exactly how to go about unlocking the M13B.
How to unlock the M13B
Unlocking the M13B is a challenge that is not given to the player. It is something that you have to figure out for yourself given the lack of direction from the game.
The whole objective that needs to be completed in order to unlock the M13B is to defeat a character called The Chemist in DMZ. He will spawn in random locations within the map, along with a circular zone of radiation.
Tracking down The Chemist is only half of the job. In order to secure the blueprint reward for the M13B, you need to take him down. This isn't the easiest of tasks, especially alone, so come prepared with an LMG and grenades. Our recommendation is to employ the use of the RAAL LMG and plenty of Semtex.
After killing The Chemist, he drops a special blueprint of the M13B on the ground. Infinity Ward named this new blueprint the Health Hazard. In order to keep it and confirm the weapon unlock, you must take it to an extraction zone and successfully exfiltrate.
A message then pops up on your screen saying that a new weapon is available. This only happens after leaving Al Mazrah. Players can then use the M13B in all other Modern Warfare 2 game modes.
All of the steps:
- Load into DMZ either alone or with your squad.
- Find the radiated zone on the map.
- Locate The Chemist within the radiated zone.
- Defeat The Chemist and acquire the M13B "Health Hazard" blueprint.
- Exfiltrate from DMZ without dying or dropping your blueprint.
A sneaky way to do it
There is a sneakier way to unlock the M13B, but you are going to need a friend who already has the weapon.
Players can unlock the M13B by loading into DMZ with a friend and having them drop the gun to pick up. After collecting the gun, extract as normal and you will also unlock the gun.
Infinity Ward may choose to have other weapons unlockable through in-game quests like the M13B in the future.
The M13B will also be available for players to buy in the store in the near future, with blueprint bundles scheduled to arrive in MW2 soon.