Overkill's casing and barrel are done in silver, with the mouth grip and trigger done in black. Overkill's name is also engraved in copperplate type on the casing, on the left side. Crosshair's name is stamped into the black mouth grip. The weapon was built by Inkwell, over a three day period, when he was busy restoring two suits of power armour for Crosshair and Mustang's personal use.
The weapon was first test fired on some Snow Pirates by Crosshair, the weapon proved effective and destructive.
Overkill looks like a "Boys" Anti-tank rifle. The ammunition clip is up top and it has a mouth grip suited for Equestrian/Zebra mouths to grip and operate. The Weapon is done in a silver paint job, with the mouth grip in black. Crosshair's name is stamped into the mouth grip, whilst the weapon's name is engraved onto the left hand side of the casing in copperplate type with a line underneath it.
The weapons barrel has small red talismans built into it, which cause the ammo fired to explode on impact.
- Overkill is a kill challenge in Fallout: New Vegas which involves killing wasteland animals with Mini Nukes.
- The weapon is based off of a Boys Anti-Tank Rifle .