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The drone cannon is a weapon of alien origin which is added to Fallout 3 in the Mothership Zeta add-on.


It is the removed arm cannon of a guardian drone.[1] It fires a ball of energy that acts as a grenade, bouncing and then exploding after a period of about 3 seconds. The projectile has the ability to move buses and cars before exploding.

This weapon is hard to use at first, but once one understands its operation, it becomes an extremely devastating weapon. A direct hit from the ball of energy will also deal high damage, and hitting a target's middle to upper body will usually result in the ball dropping straight down before exploding, making it a good way to hit specific targets with the explosion.

When fired into water, the projectile will continue normally, bouncing off any obstructions under the water. It will explode normally like other explosives.


The drone cannon can successfully fire about 417 times from full condition before breaking.


Drone cannon Ex-B - it has increased range over the drone cannon, and the projectiles fired from it explode on impact, unlike the bouncy drone cannon shot.


Weapon name (current weapon is highlighted)- Weapon name (melee or unarmed)Attacks in V.A.T.S.- Attacks in V.A.T.S.
Weapon name (current weapon is highlighted)- Weapon name (gun, energy or explosive)Action point cost- Action point cost
Damage per attack (damage per projectile)- Damage per attack (damage per projectile)Damage per action point- Damage per action point
Damage per second- Damage per secondWeapon spread- Weapon spread
Area of effect damage- Area of effect damageMagazine capacity (shots per reload)- Magazine capacity (shots per reload)
Effect damage & duration- Effect damage & durationDurability (number of attacks before breaking)- Durability (number of attacks before breaking)
Bonus effects- Bonus effectsWeight- Weight
Attacks per second- Attacks per secondValue in caps- Value in caps
Critical chance % multiplier- Critical chance % multiplierValue to weight ratio- Value to weight ratio
Critical damage- Critical damageSkill required- Skill required
Critical effect damage & duration- Critical effect damage & durationStrength required- Strength required
With all mods attached- With all mods attached
Weapon name (current weapon is highlighted)Damage per attack (damage per projectile)Damage per secondArea of effect damageBonus effectsAttacks per secondCritical Chance % multiplierCritical damageAction Point costDamage per action pointWeapon spreadMagazine capacity (shots per reload)Durability (number of attacks before breaking)WeightValue in capsValue to weight ratio
Drone cannon 40
466.7100Timed detonation3.33x150304.70.51417181999111.1
Drone cannon Ex-B 40
466.7100Impact detonation3.33x150304.70.51417181999111.1


This gun can be found on guardian drones, along with the alien power modules to power them. The cannons can also be shot off the drones and picked up like other weapons.


The guardian drones carry a different version of this weapon with the base ID of XX007BA1 with a DMG of 152, full CND, a value of 1999 and no Pip-Boy image. when the player character picks it off their body, the drone version of the weapon is removed and the player character version is added in its place.


  • Icon pc.png Icon ps3.png Icon xbox360.png When taking the cannon from a drone, it has no icon (PipOS Error - 26 [File Not Found]). [verified]
  • Icon pc.png Icon ps3.png Icon xbox360.png When examining a cannon dropped by a drone in the normal worldview (not by searching the drone's inventory), it will always show a value of 999 caps (app. half CND) regardless of the weapon's actual quality. [verified]
  • Icon ps3.png Icon xbox360.png When examining the drone cannon while in a guardian drone's inventory, the condition, damage, and value is at its highest (Full CND,152 DMG, Value:1999 caps) but when examining the drone cannon in the Wanderer's inventory, it will show its true statistics e.g. 3/4 CND,129 DMG, Value:1357 caps. [verified]
  • Icon xbox360.png If one equips a drone cannon while wearing Enclave Tesla armor, the coils on the back of the chest piece will disappear. [verified]





  1. Fallout 3 Official Game Guide Game Of The Year Edition p. 104: "Ripped from the mechanical body of an Alien Drone encountered throughout Mothership Zeta, this fires orb-like projectiles that bounce off walls and scenery and explode after around three seconds. It uses Alien Power Modules as ammunition. It inflicts two types of damage: collision (when the orb strikes a foe) and explosive (when the orb detonates). This can be extremely deadly once you learn when to fire, and how the orbs interact. It can fire over Alien Sphere Shields too, acting a little like a grenade."