The chaingun is first found in a secret area of E1M2: Nuclear Plant, and again in a secret area of the following level. It then appears in a non-secret area on E1M4: Command Control. In Doom II, it is first found on MAP03: The Gantlet (Doom II).
The chaingun contains 20 rounds of ammunition when picked up (40 on the "I'm Too Young To Die" and "Nightmare!" skill levels). Chainguns taken from fallen heavy weapon dudes contain 10 rounds (20 on ITYTD and NM) and, unlike pre-existing chainguns, disappear when crushed beneath doors or moving ceilings.
The chaingun always fires in pairs of hitscan shots, as long as the player has two bullets or more. Each bullet inflicts 5-15 points of damage. The first two shots in a volley will always be exactly on target, but if the trigger is held down, later shots will suffer from the same dispersal as pistol shots (standard deviation around 2°, to a maximum of ±5.5°).
The chaingun's rapid rate of fire means that a single enemy caught in its hail of bullets will have little or no chance to retaliate such as demons and cacodemons (except boss monsters, whose pain chance tends to be very low). The weapon is also highly effective at mowing down hordes of zombies or imps. Because its recoil does not affect the first two shots, it is an ideal weapon for sniping, as the player can tap the fire button for accurate two-shot bursts.
- As with the rocket launcher and BFG9000, the first-person chaingun sprite is slightly too large for the screen, and can only be viewed with a level or resource editor.
- The images for the chaingun in Doom are those from the "Ol' Painless" Tootsie Toy Gatling Gun, a motorized, electronic toy gatling cap gun.
- The target of chaingun fire often appears to turn and shuffle rapidly in place, due to the continual interruption of its sprite sequences. Doom's instruction manual refers to this motion as "the chaingun cha-cha."
- The firing animation for the Chaingun is different in PSX Doom. In the PC version, the muzzle flash is continuous, whereas it blinks in the PSX port.
- The chaingun first appeared in the Doom press release beta. Its graphic was slightly different, in that the tips of the barrels did not extend past the barrel band.
- If the chaingun is associated with real weaponry, it is actually a portable Gatling-style weapon similar to a minigun. An actual chain gun has a single barrel.
- The chaingun also feeds from magazines, which is rather unusual for a gatling gun, as gatling guns are generally belt-fed.
- As with all firearm hitscan attacks, the damage inflicted per bullet by the player's weapon is slightly higher than that of monsters using equivalent attacks.
- In the Saturn port, the chaingun fires much faster than in other ports.
|Damage||5-15 per bullet|
|Included ammo||20 (40 on skill 1 & 5)|
|Max ammo||200 (400 with backpack)|
|Shots per minute||525.0|
|Appears in||Shareware Doom|
The Ultimate Doom
Doom II/Final Doom
|Thing type||2002 (decimal), 7D2 (hex)|
|Sprite||MGUN (before pickup)|
PUFF (impact, miss)
BLUD (impact, hit)
|Shots needed to kill1,2||Mean|| Standard
|Heavy weapon dude||7.12||1.10||5||11|
|Baron of Hell||97.06||4.32||87||107|
- This table assumes that all calls to P_Random for damage, pain chance, blood splats, and bullet dispersal are consecutive. In real play, this is never the case: counterattacks and AI pathfinding must be handled, and of course the map may contain additional moving monsters and other randomized phenomena (such as flickering lights). Any resulting errors are probably toward the single-bullet average, as they introduce noise into the correlation between the indices of "consecutive" calls.
- In the case of continuous fire, the target must be close enough to compensate for the weapon's recoil.
- Assumes that direct hits are possible, which does not occur in any stock map.
The IWADs contain the following numbers of chainguns per skill level (excluding those from fallen heavy weapon dudes):
In Doom 64, the chaingun is depicted with longer perforated barrels, and a worn blue tone, rather than its counterpart's polished steel appearance. Additionally, it has a smaller blue muzzle flash. The pickup sprite has a somewhat rusty appearance as well. When fired at a consistent rate, the screen will jerk up and down rapidly.