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 half a 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. In comparison to the other two rapid-fire weapons - the machine gun and the plasma gun - the chaingun has the highest damage output of the three. However, it is less accurate than the machine gun and plasma gun, and ammo is generally less commonly found especially in the early parts of the campaign.

The BFG Edition reduces the chaingun's rate of fire from roughly 9 shots per second to roughly 8, reducing its overall damage output. Nonetheless, it still has a higher overall damage output than the machine gun and plasma gun.

Tactical use[edit]

The Doom 3 protagonist carrying a chaingun

The chaingun is suitable for a variety of situations. Its overall damage output is roughly twice that of the machine gun, although it suffers from less accuracy and a brief spin-up delay. For these two reasons, it is generally more useful for sustained fire against larger, more durable foes - demons or anything tougher than that. It has the necessary firepower to engage the strongest foes, even Hell knights, mancubi and arch-viles. It is the best choice during the first encounter with the Vagary, having the highest damage output of any weapon available at that point.

The chaingun suffers from a brief delay, around half a second, for the barrel to spin up before firing (although it is possible to mitigate this by "pre-spinning" the chaingun, and keep it revved). This can be disadvantageous for the player against certain foes such as Z-Secs, allowing them the chance to hit the player first. For this reason, the machine gun may be the better choice against Z-Secs. Furthermore the chaingun has less accuracy, so the machine gun may be the better choice against smaller foes such as cherubs, lost souls and Forgotten Ones.

Ammunition for the chaingun is somewhat rare in the early stages of the campaign, particularly before the player reaches the Delta Labs, so it is wise to use it rather sparingly.

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) 8-9*
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 BFG Edition reduces the chaingun's rate of fire. In the original game, it takes around 6.5 seconds to deplete a full belt of 60 bullets, so roughly 9 shots per second. In the BFG Edition, it takes around 7.5 seconds to deplete a full belt, so roughly 8 shots per second. In both cases, this does not count the brief spin-up delay before the chaingun can fire (less than half a second).
  • 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.