Experimental MIRV

The Experimental MIRV is an even more powerful version of the Fat Man nuke launcher that fires eight nukes at once. While it is visually identical to the Fat Man launcher, it delivers eight mininukes spread over an area for each shot. It requires 8 mininukes to fire, any less and it will tell you ammo is depleted. Fortunately, 5 mininukes are found right next to it, and another is encountered while searching for the Keller Family letters required to gain access to the MIRV.

When fired, the weapon behaves somewhat like a shotgun, in that the projectiles fire in a random spread pattern. However, unlike a shotgun the projectiles are subject to the same arcing behavior as the normal Fat Man. If you can get lucky with the spread, this weapon will insta-kill a Behemoth and then some at medium range.

You must find all five Keller Family Tapes to gain access to the armory inside the National Guard Depot. Inside along with the MIRV Fatman is a glowing ghoul along with the remains of the unfortunate Keller Family.