Callahan's Magnum

 is a weapon which was added to Fallout 3 with the Broken Steel downloadable content pack.

Callahan's Magnum is a unique Scoped .44 Magnum that surpases the Blackhawk (the other unique Scoped .44 Magnum) in damage, damage per second and AP Cost. Depending on equipment and perks, the weapon can fire 1-2 more shots in V.A.T.S. than the Blackhawk.

Trivia

 * The weapon's name is a reference to Harry Callahan from the Dirty Harry movies who carries a .44 Magnum as his signature weapon.