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Experimental MIRV

Last edited on February 23, 2014
by Anonymous
Experimental MIRV
Fat Man
Fat Man icon
skillBig Guns
Attack statistics
80 (89) + 12800 (13445) explosion
Icon explosion
10 (11.1) + 1600 (1680.6) explosion
Icon explosion
20336.2 (21368.8)
DPS (reload)
3544.9 (3724.9)
crit dmg
crit % mult
Ammo & reloading
ammo typeMini nuke
ammo cap.8
reload time
item HP300
Fat Man
questsKeller Family Refuge
base id0003422b

The experimental MIRV is a weapon in Fallout 3.


The experimental MIRV is a unique Fat Man that can be found in the bomb shelter area in the National Guard depot. This weapon deals the most damage of any weapon in the entire game, as it acts like a shotgun version of the Fat Man, delivering eight mini nukes at once. The MIRV actually does the same damage as a Fat Man per mini nuke, as 12,880/8 equals 1,610. This means that the MIRV is simply a Fat Man with extra capacity and increased ammunition usage. It will not fire if you don't have at least 8 mini nukes in your inventory to load it with. If you have fewer than 8 mini nukes, the weapon will reload but never discharge the payload.


The Experimental MIRV can fire a total of 63 shots, the equivalent of 504 mini-nukes, from full condition before breaking.


  • Fat Man - The common variant in Fallout 3.


Weapon name (current weapon is highlighted)
Icon gun
Damage per attack (damage per projectile)
Icon damage
Damage per second
Icon dps
Area of effect damage
Icon explosion
Bonus effects
Icon bonus effect
Attacks per second
Icon attack
Critical Chance % multiplier
Icon chance
Critical damage
Icon critical damage
Action Point cost
Icon action
Damage per action point
Icon dap
Weapon spread
Icon spread
Magazine capacity (shots per reload)
Assault carbine extended magazines
Durability (number of attacks before breaking)
Icon repair
Icon weight
Value in caps
Icon merchant
Value to weight ratio
Icon ratio
Fat Man 10
25421600+10 radiation
Icon radiation
Experimental MIRV 80
20336.212800+80 radiation
Icon radiation


The player must complete the unmarked quest Keller Family Refuge before they can gain access to the secure section of the depot housing the weapon.

It's also possible to gain entrance to the armory by using a glitch.


  • The MIRV looks identical to the Fat Man, meaning only 1 mini nuke appears to be loaded on to the weapon; however the game overlaps all eight mini nukes, which separate upon exiting the weapon.
  • Sometimes the MIRV (or Fat Man), is set up such that using it in V.A.T.S. will cause the player to aim directly at the enemy, without aiming upwards to compensate for the distance. This, coupled with the fact that only the 8th nuke shot out of the MIRV will go as far as the Fat Man's single nuke (and all other nukes will travel shorter distances), means that using the MIRV in V.A.T.S. will cause the player's death.
  • If you look directly at the ground and fire the MIRV, the 8 mini nukes' combined power is enough to launch your dead body to the height limit (roughly the height of Tenpenny Tower).
  • Similarly, the MIRV can potentially send the bodies of human enemies hit by multiple mini nukes flying hundreds of feet into the air, potentially rendering their bodies impossible (or very hard) to find. Keep this in mind before using the MIRV on an opponent whose body you want to loot.
  • It costs more to fire this weapon once than it does to repair a regular Fat Man twice. At several hundred caps per nuke and firing eight nukes per shot, this is the most expensive weapon in the game, albeit the most powerful.
  • Depending on your game system, its age, and the amount of excessive use of the MIRV, it may cause your system to lag and possibly crash.
  • Out of every weapon in Fallout 3, the MIRV is the most powerful in terms of base damage.
  • Considering everything mentioned above, the experimental MIRV is one of most inefficient, unnecessary, and impractical weapons in the game. However, with an ammo console command (PC), this weapon can easily take down large groups of more powerful enemies (e.g. super mutants, Enclave, and deathclaws).

Behind the scenes

MIRV is a military term for Multiple Independent Reentry Vehicle (or Multiple Independently Targetable Reentry Vehicle). It is a collection of nuclear weapons carried on a single intercontinental ballistic missile (ICBM). Using a MIRV warhead, a single launched missile can strike several targets, or fewer targets redundantly. The MIRV system was developed throughout the middle of the 20th Century, and one of the main ideas behind the weapon system was to take out an enemy country with a single missile attack before the enemy nation could be able to respond.


  • xbox360
    Icon xbox360
    Sometimes a graphics error can occur when detonation is very close. It can cause large, black rectangles to extend from the weapon out to as far as you can see. A console restart will fix this. [verified]
  • xbox360
    Icon xbox360
    Icon pc
    Sometimes when lifting the item, it will twirl around in the air, making it very hard to decorate your Megaton house or Tenpenny suite with it. [verified]


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