Chaingun (Doom 3)


The Chaingun.
This article is about the weapon in Doom 3. For other versions of this weapon, see:

The chaingun (also known as the UAC Weapons Division Mach 2 Chaingun) in Doom 3 is a mid-range weapon with a high rate of fire. It is considerably more powerful than its classic Doom counterpart. While the old chaingun was, at best, a light rapid fire weapon that was clearly inferior to the original plasma gun and at best compared to the machine gun, Doom 3's chaingun is more on par with its plasma gun.

"The Chain Gun's 0.30 caliber armor piercing round delivers substantial damage, but heavy recoil reduces accuracy."
PDA description

Weapon schematics[edit]

The Doom 3 chaingun differs from its original; there is a slight wind-up time (around 1 second) for the barrel array before it begins firing. Also, unlike the classic chaingun, which fired the same standard rounds as the pistol, the Doom 3 chaingun now utilizes exclusive .30 caliber armor penetrating rounds, easily outclassing the pistol and machine gun in terms of firepower. Ammo for the chaingun is in the form of ammo belts (60 rounds) which appear as ammo cans about the size of a briefcase, and can also be obtained by picking up chainguns (30 rounds) from deceased chaingun commandos. Just like the BFG 9000, plasma gun and newcomer machine gun, the ammo counter is located on the weapon itself, instead of the game HUD. Like the machine gun, the chaingun has a built in "buzzer" alarm which activates when players are reduced to 10 bullets in their current clip, suggesting the player to reload.

Tactical use[edit]

The Doom 3 protagonist carrying a chaingun

The chaingun is suitable for a variety of situations. Reasonable accuracy and rate of fire make it a good weapon to use in anywhere from close to far range situations against almost any low to mid-range foe. Even a Hell knight can be taken down with less than five seconds of concentrated fire.

Although it has stupendous firepower at any length, the weapon suffers from very high recoil. This, in turn, makes the weapon have a slower rate of fire compared to the machine gun and plasma gun, and also reduces accuracy from continuous fire.

Additionally, the chaingun suffers from a one second lag caused by it's wind-up time for the barrel. This can be disadvantageous for the player at close range, as it will give enemies enough time to land a first attack, before the it can start firing. However, it is possible to "pre-spin" the chaingun, and keep it revved, reducing the lag to allow it's effectiveness in tight quarters.

The chaingun has no splash effect damage, meaning that unless the target stands perfectly still or the user just fires blindly in the target's movement range (which means wasting ammo), not much damage will be inflicted.

The best situation is a relatively slow, large monster that affords enough time to be taken down and requires a steady stream of fire to be taken down, such as pinkies, cacodemons and the Vagary. Also, a group of trites or lost souls can easily be taken down with some blind firing.

As chaingun ammunition is generally hard to find until the player reaches the Delta Labs, it is recommended to use the plasma gun as a replacement for all levels leading up to the aforementioned.

Mach-2 Chain Gun Briefing (Video disk)[edit]

Creator: UAC Advanced Weapons
Date: 03/20/42
Informational video on the Mach-2 Chain Gun

In a quest to provide armies with a well balanced set of weapons, the UAC looked to the past when designing and manufacturing the newest line of Mach-2 Chain Guns. The retro style and mechanical sturdiness of the Chain Gun is a must for all hardened combat veterans.

Early adapters have nicknamed it "Saw". With its armor piercing .30 caliber bullets, the Chain Gun is capable of literally cutting opponents in two. Packed with all the punch you need in close combat fighting the Chain Gun delivers unparallelled reliability and functionality.

Always on the forefront of technology, the UAC is making safer worlds through superior firepower.


The HUD icon.
Mach-2 Chaingun
Normal damage 20 25
Headshot damage 40 50
Rate of fire (RPS) 10
Reload time (sec) 2.08
Ammo capacity 60
Ammo in: pack/weapon 60*/30
Max ammo 600
Velocity 2,000 20,000
Spread (°) 5 1
Ammo type Ammo belt
First seen in Administration

  • The chaingun is the only weapon whose ammo packs contain a different amount of ammo in multiplayer, at 120.


The chaingun first appears in the Martian Buddy storage locker in Administration. It can also be found - along with several ammo belts - in the really dark areas of Alpha Labs Sector 2 through which Edwards, the lantern man, will guide the player.

The chaingun's rate of fire is linked to the game's FPS rate. If the game is being played at 60FPS, it will fire more slowly than it should; this can be changed in the Settings menu by increasing the FPS to 120.