Icon disambig
For the weapon in Fallout Shelter, see MIRV (Fallout Shelter).

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 of 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. It will not fire if the Lone Wanderer doesn't have at least 8 mini nukes in their inventory to load it with. If they 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.


Icon melee- Weapon name (melee or unarmed)Icon sequence- Attacks in V.A.T.S.
Icon gun- Weapon name (gun, energy or explosive)Icon action- Action point cost
Icon damage- Damage per attack (damage per projectile)Icon dap- Damage per action point
Icon dps- Damage per secondIcon spread- Weapon spread
Icon explosion- Area of effect damageAssault carbine extended magazines- Magazine capacity (shots per reload)
Icon effect- Effect damage & durationIcon repair- Durability (number of attacks before breaking)
Icon bonus effect- Bonus effectsIcon weight- Weight
Icon attack- Attacks per secondIcon merchant- Value in caps
Icon chance- Critical chance % multiplierIcon ratio- Value to weight ratio
Icon critical damage- Critical damageIcon ability- Skill required
Icon crit effect- Critical effect damage & durationIcon fist- Strength required
Icon plus- With all mods attached
Icon gunIcon damageIcon dpsIcon explosionIcon bonus effectIcon attackIcon chanceIcon critical damageIcon actionIcon dapIcon spreadAssault carbine extended magazinesIcon repairIcon weightIcon merchantIcon ratio
Fat Man 10
25421600+10 Icon radiation/12s1.58x006524.82.0116730100033.3
Experimental MIRV 80
20336.212800+80 Icon radiation/12s1.58x0065198.213.08(1)6330249883.3


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, though it's also possible to gain entrance to the armory by using a glitch. See the bugs section on National Guard depot for more details.


  • 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 character to aim directly at the enemy, without aiming upwards to compensate for the distance or mini nuke drop. 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 usually cause the player character's death.
  • If the player character looks directly at the ground and fires the MIRV, the 8 mini nukes' combined power is enough to launch their dead body to the height limit.
  • 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.
  • 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.
  • Out of every weapon in Fallout 3, the MIRV is the most powerful in terms of base damage.

Behind the scenesEdit

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.


  • Xbox 360Icon 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]
  • PCIcon pc Xbox 360Icon xbox360 Sometimes when lifting the item, it will twirl around in the air. [verified]
  • PCIcon pcIf you equip the weapon and enter V.A.T.S. while having less than 8 Mini nukes, V.A.T.S. will not show you the "not enough ammo" box, but if you actually try to use it the weapon will not shoot and you will get stuck in the V.A.T.S. sequence, reloading a save will fix the problem. [verified]




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