Lincoln's Repeater (Fallout 3)

Lincoln's Repeater is a .44 rifle, with a 15-round magazine, found in Fallout 3. It is located, in perfect condition, inside of a display case in the top floor of the Museum of American History offices. Despite its .44 ammunition, it should be considered in the same category as a Hunting Rifle (with higher accuracy, comparable to sniper rifle), as it uses their parts for repair.

Upon entering the Museum of American History, make your way to the Lower Levels, which is located on the left as you enter the big room with the giant prehistoric animals. (Be aware that there are a large number of feral ghouls in here. Make sure you have a good weapon and possibly some health before you attempt this.) Once in there, walk up the left staircase and go into the room filled with empty (or destroyed) displays and enter the offices door on the left side of the room in the back. Make your way through the offices until you come to a large, open room with a turret on the ceiling. Walk up the staircase that is against a wall in the front of the room. Upon reaching the top, you should see a giant hole in the wall. Once you reach the top, however, more Ghouls are waiting for you along with a Glowing Ghoul. This guy is pretty tough if you're a low level so make sure you have a strong weapon. Go in the giant hole, and in furthermost cubicle on the left you should find the rifle waiting inside a display case on a desk. Alternatively, you can just walk by them all without being attacked if you are wearing the Ghoul Mask.

It fires .44 Round, Magnum ammunition, but is repaired with Hunting Rifle parts. The rifle is devastating when used with the Commando and Sniper perks, which boost rifle accuracy in V.A.T.S. This is easily the best medium-to-long range small guns rifle in Fallout 3 as it combines accuracy, high damage, a large magazine, and low AP requirements. On normal difficultly, sneak attack headshots (with a decent small guns skill) using this weapon will kill anything instantly bar Giant Radscorpions, Deathclaws, Super Mutant Behemoths and most robots (Brainbot and Protectron being the exceptions).

You can also sell this to Leroy Walker who occupies Lincoln Memorial and will destroy it to erase Lincoln's legacy. Otherwise, you can also sell it to Hannibal Hamlin after receiving the Head of State quest, who will enshrine it. In addition you can sell this to Abraham Washington in Rivet City. Note that the price may be a lot less than its specified value (which is depending on condition, up to 500 - Remember that you can repair this powerful weapon with parts from the common Hunting Rifle).

Trivia
This weapon is speculated to be based on the 1860 Henry Rifle, a .44 caliber black powder cartridge (known as a.44 Henry round) rimfire rifle, although it has a wooden hanguard in front, very similar to a Winchester Model 1866. Though it would seem to be plausible to use .44 magnum ammunition in the rifle with slight modifications, the pressure from the modern cartrige would be far too much for the firing chamber to handle.