That Gun

That Gun is a unique 5.56mm pistol

Gameplay
That Gun weighs 5 pounds and when reloading, the weapon's cylinder mechanically swings open to the left and auto-ejects the spent casings. The green light on the left side of the gun turns yellow while reloading and then turns green while making a ringing noise once the weapon has reloaded.

Until the release of the add-on Gun Runners' Arsenal, That Gun was the only pistol capable of using dedicated armor piercing rounds. That Gun is also the least expensive, named rare gun that is available for purchase in Fallout: New Vegas.

Durability
That Gun can fire about 1120 standard rounds, the equivalent of 224 reloads, from full condition before breaking.

Variants

 * 5.56mm pistol

Location
The weapon is located in Novac, inside the Dino Bite gift shop. It can either be purchased from Cliff Briscoe or stolen from the storage room. It is on the end of the first shelf with the rocket souvenirs to the right. The storage room key can be pick-pocketed or alternatively the Very Easy lock can be picked. The key may also be purchased during the quest Come Fly With Me or any time after its completion.

Behind the scenes
According to Joshua Sawyer, its name is derived from the fact that many players referred to the .223 pistol as "That Gun" in Fallout and Fallout 2.

Bugs

 * If That Gun is stolen from the storage room, Cliff Briscoe may still sell it in his shop, creating the possibility of obtaining a second weapon.
 * If loading a saved game from the main menu in which That Gun is equipped and drawn, the reload animation takes twice as long as normal. This can be solved by simply switching to another gun and then back again.
 * That Gun is not affected by The Professional perk. Curiously, its non-unique counterpart, the 5.56mm pistol, is.
 * Rarely, when aiming down the sights of That Gun, when turning right or left the camera will instead pivot from the Courier's shoulders, but the gun will stay in the same spot, causing it to careen to the right and left. One's head can even be moved backwards, to the point of seeing the viewmodel hands.