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The mini nuke is a type of ammunition in Fallout 76.


Developed at Fort Strong as part of the M42 Fat Man project, the mini nuke is one of the most powerful conventional weapons ever devised. Though the project was plagued by design issues from the beginning, caused by the weight of the micro-nuclear warhead and the resulting low range, the designers eventually happened upon a breakthrough: Instead of trying to reduce the weight of the warhead or the power of the launching system, one researcher proposed falling back on the spigot mortar system, used over 130 years before in PIAT launchers. The ingenious solution was just what was needed to complete the project and by September 2077, the first M42 Fat Man weapon systems were sent to ordnance depots across the United States.[1][2][3]

The mini nuke consists of four principal components. The detonator shell on the bottom contains a conventional sub-charge that detonates when struck by the M42's striking pin, catapulting it out of the launcher. Four stabilizer fins attached to it ensure a stable trajectory and prevent tumbling in flight, increasing accuracy (a necessary feature, as the projectile is not spin-stabilized). The hemisphere core is screwed onto the top, containing the nuclear core. Finally, the weapon is fitted with a beryllium contact fuse that starts the nuclear reaction on impact.[4][5][6]


A small, football-sized nuclear bomb, mini nukes are as rare as they are powerful and are the heaviest explosive munitions in the game, weighing at 6 lbs per nuke. Mini nukes and the Fat Man can be a desirable choice for taking down high health enemies. However, a single mini nuke blast is enough to kill people too close to it.


Lead (3)
Screw (10)
Steel (10)
Build at:
Learn Method:
Learned on pickup
Ammosmith (optional)
Ammo Factory (optional)
Mini nuke (3)

Weapons using this ammunition


  • Crafted at a tinker's workbench.
  • Can be traded at an Ammo Converter.
  • Four can be found at Fort Defiance in the armory:
    • Two on the third floor, on the bottom row of a metal shelf with a footlocker above, in the locked armory room near the overseer's cache.
    • Two on the fourth floor, in the locked armory near the overseer's cache, on the middle row of a metal shelf.
  • Two can be found northeast of Fort Atlas, at an unmarked Brotherhood checkpoint on the map, on the curving highway, inside an open wooden crate.
  • One can be found at Hornwright Industrial Headquarters.
  • One can be found at the Whitespring Resort on top of the gatehouse, near a skeleton, at the northeast entrance across from the Whitespring station.
  • One can be found in the Burning Mine in the eating area that lies close to the hospital room.
  • One can be found at US-13C Bivouac - On a table inside the bottom left tent near the broken terminal.
  • One can be found at the Twin Pine Cabins - In the same shack as a weapons workbench, to the left.
  • One can be found at the Sons of Dane compound - Inside the house, on the metal shelf in the Picklock level 3 basement storage, closest to the power armor chassis spawn.
  • One can be found at the Middle Mountain Cabins - Inside the toolshed, on a crate.
  • One can be found at Drop Site C2 - On some shelving to the left of the front desk.
  • One can be found at Drop Site G3 - Below the slanted metal shelf on the left.
  • One can be found at Drop Site V9 - On top of the cabinet, to the right of the wooden crate and left of the Picklock 3 safe.
  • One can be found at Hornwright testing site 2 - Inside the Picklock 2 room, on the middle metal shelf, on the bottom row, to the left.
  • One can be found at The Sludge Works - On a metal barrel, behind the bar.
  • One can be found at Skullbone Vantage - In the northwest tent.
  • One can be found at Forward Station Delta - On a wooden slab to the right of the power armor station.
  • One can be found at Watoga Emergency Services - On the roof, to the left of an industrial trunk.
  • One can be found at Watoga High School - Inside a Picklock 2 window in the headmaster's office along the western wall.
  • One can be found at Watoga Transit Hub - Inside the locked room on the first floor, on a metal shelf next to the doorway.
  • One can be found in The Deep - On the top floor of the main facility, on the edge of a green container facing the southern wall.
  • One can be found at the RobCo Research Center - On the ground next to the first console to the left of the entry to the robotics technology facility.
  • One can be found at Sunnytop Ski Lanes - On the lower level, in the middle locker facing the northwestern wall near the counter.
  • One can be found at Grafton Dam - On a guard tower outside the dam's building closest to the entrance with the terminal, next to the yellow spotlights.
  • One can be found at Black Mountain Ordnance Works - Within TNT dome #7, on a yellow recharging table.
  • One can be found at Nicholson's End - In the easternmost trailer, next to the radio in front of the doorway.
  • Rarely dropped by feral ghouls.
  • Sometimes dropped by super mutant suiciders if their cause of death was before nuke detonation.


With the Ammosmith perk or Ammo Factory legendary perk, the crafted amount of mini nukes increase incrementally, coinciding with the perk's added percentages, crafting more bombs for the same amount of materials.


  1. Fort Strong terminals; Bravo Team Testing Terminal, Bravo Team M42 Report 001: "Things are getting tough around here. Brock has decided to split our men into two teams. I drew one of the short straws, so I ended up on the M42 "Fat Man" Launcher team while most of my buddies are sitting pretty upstairs with the T-51B suits. I can't even begin to describe what a ridiculous idea the M42 is - a man-portable mini-nuke thrower that a trooper in the field is supposed to deploy at close range. I've been pouring over the schematics and I have no idea how were going to get this thing to throw a warhead far enough not to kill the soldier unlucky enough to be stuck with these deathtraps."
  2. Fort Strong terminals; Bravo Team Testing Terminal, Bravo Team M42 Report 002: "We've stripped the warhead weight down as much as possible, but I think we're looking at this the wrong way. Instead of trying to reduce the warhead weight, we should try and amp the power on the thrower itself. I know that means adding weight to an already heavy piece of ordinance, but I don't think we have any choice. One of the guys suggested we try magnetics to push the warhead through like a rail gun, but the power pack would need to be the size of a suitcase. I'll keep picking away at this problem and see what I can turn up."
  3. Fort Strong terminals; Bravo Team Testing Terminal, Bravo Team M42 Report 003: "We lost two good soldiers this morning. They were on the surface testing a MIRV variant of the launcher, when one of the warheads misfired and hit the ground right where they were standing. Poor bastards didn't even have a chance. We couldn't even find any remains to send home to their folks, so Brock told us to just fill some cans with sand. I'll tell you, that guy doesn't give a crap about us, he's just worried about the brass back in Washington giving him a hard time."
  4. Fort Strong terminals; Bravo Team Testing Terminal, Bravo Team M42 Report 004: "I was in bed last night when I had one of those "Eureka" moments. I ran over to the night shift guys in the lab, swept all of their drawings on the floor and starting sketching my idea. They must have thought I'd lost my mind. Six hours and about fourteen cups of coffee later, and I had it all mapped out. We'd use a small sub-charge as a launching catalyst to catapult the warhead from the launcher. We'd have plenty of range, and the sub-charge could be built into the warhead itself. Brock seemed to like the plan and gave us the go ahead to prototype the device. I can't wait to try it out."
  5. Fort Strong terminals; Bravo Team Testing Terminal, Bravo Team M42 Report 005: "It took the better part of a year, and over a hundred test firings, but the M42 is ready to shipped out into the field. I can't believe I spent over a year on this single project. I feel pretty good knowing we're delivering a well-tested weapon to our own guys fighting overseas. Now that it's over, I suppose Brock will move us on to something else, but for now I'm going to spend the rest of the month packing up these warheads to ship off base."
  6. Fort Strong terminals; General Brock's Terminal, General Brock's Report - December 2076: "Bravo Team is having a heck of a time getting the M42's not to shoot far enough away from its firing position. The problem is that the warhead is still too heavy to fire the distance required - our simulated soldiers are still soaking far too many rads and suffering blast burns. One of the technicians has suggested a radical idea of using a conventional depleting sub-charge to catapult the round rapidly out of the launcher. His calculations look sound, so I am going to let him give it a try."