Callahan's Magnum

 is a weapon which was added to Fallout 3 with the Broken Steel add-on.

Characteristics
Callahan's magnum is a unique scoped .44 magnum that surpasses the Blackhawk (another unique scoped .44 magnum) in damage, damage per second, and AP Cost. Callahan's magnum can fire 205 rounds before breaking from 100% condition, or about 34 full cylinders. That's 23 rounds less than the normal scoped .44.

Location
It can be found in a hard safe within the ruins of the Citadel if you choose to destroy it while onboard the Enclave Mobile Base Crawler during the Who Dares Wins quest. Enter the door at the bottom of the crater, head up the stairs, and enter the cubicle against the far wall. The safe requires 75 Lockpick, but there's also a terminal you can hack with 75 Science.

Behind the scenes

 * The weapon's name is a reference to Harry Callahan from the Dirty Harry movies who carries a Smith &amp; Wesson Model 29 .44 Magnum as his signature weapon, even though in the films it was never scoped. Indeed, if you use Callahan's terminal to unlock the safe, it is revealed that this certain Callahan's first name was "Harold"!

Videos
Video:Fallout 3 Broken Steel - Callahan's Magnum