"Energy based weapon developed in the Mars weapon facility. Unit is powered by plasma canisters manufactured in the EnPro facility."
PDA Description [src]

The Series 3 Plasma Gun in Doom 3 is an energy-based weapon first found in a hidden location in Sector 3 of the Alpha Labs. This weapon fires pale-blue globular bursts vaguely reminiscent of tiny stars.

Weapon Schematics


A blueprint of the Plasma Gun.

The Plasma Gun is slightly different from its earlier counterpart, as the projectiles now move at visibly slower speeds. Nevertheless, it still possesses effective firepower, making it comparable to the higher-end weapons such as the Chaingun and the Rocket Launcher.

Similarly to the Chaingun, BFG 9000 and newcomer Machine Gun, the Plasma Gun discards the game ammo HUD because it has its own ammunition counter in a small monitor located at the rear upper end of the weapon itself. Ammunition comes in the form of Plasma Cells, which appear to be bulky bottles that glow a luminescent blue and possess a blue-colored tip. Stray plasma bottles hold 25 units of projectile, whereas a box of 2 bottles holds double the amount. Ammunition for this weapon are generally easier to locate throughout the entire game relative to Rockets, Ammo Belts, and BFG Cells, and are particularly abundant in the EnPro facility.

Tactical Use

Doom3 weapons 07

The Plasma Gun before being picked up.

The Plasma Gun has a decent damage-per-shot ratio, a good rate of fire, and perfect accuracy. Its primary limitation is the slow speed of the projectiles. The Plasma Gun should be employed in short to medium range, but its accuracy makes it effective at long range as well, particularly if the enemy is large and/or not moving much. All short-range monsters make easy target practice for the Plasma Gun, but ammo should be conserved for stronger monsters such as the Revenant and Hell Knight. The slow speed of the projectiles means that flying monsters, such as Cacodemons, can be very difficult to hit unless at very short range; the hit-scan chaingun is recommended against them.

Because the Plasma Gun's projectiles are very large and fire with perfect accuracy, it is effective at destroying certain enemy projectiles; the slow-projectile, rapid-fire Plasma Gun can create a "flak zone" to eliminate the Revenant's and Mancubus' projectiles in-flight, but it is generally easier to dodge the slower and non-homing projectiles of the Imp, Hell Knight, and Cyberdemon.

Video Disk - Series 3 Plasma Gun Briefing

This video disk can be picked up in the Combat Prep room in Mars City.

Note: The video disk cannot be picked up after returning from the old comm facility.

Creator: UAC Advanced Weapons'Date: 07/28/44
Informational Video on the Series 3 Plasma Gun
Representing yet another great accomplishment of the UAC, the Series 3 Plasma Gun is an extremely versatile, medium range combat weapon. Harnessing the exhaustive resources of synthetic plasma, the plasma gun meets the critical requirement of low cost, abundant ammunition for today's highly mobile military.
Capable of sustained firepower due to the latest advancements in plasma injector technology, this weapon's light weight and high yield make it desirable for most combat scenarios.
Always on the forefront of technology, the UAC is making safer worlds through superior firepower.


  • The Plasma Gun no longer uses the same ammunition as the BFG 9000.
  • Strangely, the Plasma shots can flip away slain enemies like a light feather. This also applies to heavier foes like the Hell Knight or the Mancubus. No other weapons share this trait, as upon death, enemies will either collapse or get thrown off at a short distance from splash damage.
  • The first bit of ammo for the Plasma Gun you can find is in the Mars City Underground, hidden in a utility locker along with a Health Dispenser.
  • The Plasma Gun can be seen in the first level of the game in an armory at Marine Headquarters, but you don't obtain it until later.
  • The Plasma Gun is a very wanted weapon around Mars City, given a mention of it in a citizen's email and on a video disk found in a weapons storage room at Mars City.
  • Theresa Chasar is credited for researching the Plasma gun.
  • Sometimes, the Plasma Gun can even destroy BFG cells from the Sabaoth fight in the CPU Server Bank. The player won't take damage if it uses the Soul Cube wisely to take him out in seconds.
  • The two Plasma Guns available in the final level, Primary Excavation, are multiplayer models. This does not affect their behavior though, because the game is flagged as single player; but it does give the player 30 ammo on pickup instead of the regular 50.
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