Ol' Painless (Fallout 3)

Ol' Painless is a slightly more powerful .32 Hunting Rifle.

Characteristics
Ol' Painless does slightly more damage per shot, has a slightly faster rate of fire, reloads slightly faster than the regular Hunting Rifle, and also has a good durability and can be repaired with ordinary Hunting Rifles. Ol' Painless is one of the few weapons with 0 spread, meaning non-VATS shots go exactly where you aim them.

Thanks to its common ammo type, solid damage, and decent rate of fire, Ol' Painless is a very practical multi-purpose Small Gun. On normal difficulty, players with a well-maintained Ol' Painless, high Small Guns skill and the Better Criticals perk can kill Super Mutant Brutes or even Yao Guai with a single Sneak attack critical head shot. Even Deathclaws can be dispatched safely from distance with three or four shots, potentially before they'll even know you're there. Paired with a set of Ranger Battle Armor (which will boost both your Small Guns skill and your Luck), this weapon becomes surprisingly more effective than its numbers might indicate.

While hardly the most flashy or visually impressive weapon in Fallout 3, this weapon is deadly with the right combination of skills and perks.

Location(s)

 * In an unpickable safe in The Republic of Dave Capitol Building. Dave's special key required to open the safe.
 * You can get the key by pickpocketing Dave.
 * You can also get the safe open by successfully electing another member of the family. When Bob is elected he would say he needs to throw out Dave's junk. If Rosie is elected, she would give you Dave's items as your "reward" for helping her. Even so taking from the safe is still considered stealing (Likely a bug). If you take Ol' Painless from the safe and then speak to someone from the town, it is possible they will take it from you. If this occurs the only way to get it back is through more negative karma of either pickpocketing it or killing them and looting it.
 * You can obtain the key if you have the "You Gotta Shoot 'Em in the Head" quest as well. Through speech checks, Dave gives you his keys as an item to show Mister Crowley that he is dead, when in fact he is alive. This key can be used to unlock his safe containing Ol' Painless. To avoid getting caught stealing, either use a stealth boy or tell everyone in town to vote in order to make him move out of the room to check the ballet box.
 * If you choose to kill Dave, you will be attacked by both of his wives (FYI: he's a polygamist). Also note that it is possible that the other residents of the Republic may be unaware of your killing Dave and his wives, and thus letting you escape the Karma loss.  Another option is to declare war on the Republic and everyone will turn hostile so you can kill them with no Karma loss.
 * Occurrence of Ol' Painless in the locked unpickable chest (Muddy Rudder Supplies) inside Muddy Rudder bar in Rivet City is a random event. Belle Bonny's Key (carried by no one other than Belle Bonny) is required to open the chest, the key cannot be pick-pocketed. Another possibility of obtaining Ol' Painless is to go to Evergreen Mills and go in to the bazaar, if you break in to Smiling Jack's storage with his key you may find alot of random things inside, like several suits of power armor, rare weapons such as gatling laser, Mr. Tenpenny's suite key and Ol' Painless. It is likely that this way of obtaining the weapon is a glitch.

YouTube Videos
Obtaining Ol' Painless 3jzjR7YyoG4