10mm pistol

The Colt 6520 is a pistol with a revolving cylinder and is a highly durable and efficient weapon. It was developed by Colt Firearms prior to Great War and chambered for the common 10mm round. It proved to be resistant to the desert-like conditions of the post-nuclear wasteland and is a fine example of workmanship and quality construction (at least for the pre-War models, which became more scarce over time). The simple design of the gun allows it to be easily manufactured with relatively basic equipment, making it possible to be replicated in workshops in the post-nuclear world. The Colt 6520 is capable of chambering the 10mm hollow point round or the 10mm armor piercing round.

The Colt 6520's durability, reliability, and simple design makes it very popular among wasteland denizens, for whom sophisticated high maintenance weapons would be a liability to survival.

10mm Pistol is a Fallout and Fallout 2 weapon. In-game description: A Colt 6520 10mm autoloading pistol. Each pull of the trigger will automatically reload the firearm until the cylinder is empty. Single shot only, using the powerful 10mm round.

Behind the scenes
The 10mm pistol is a reference to the Hard Boiled comic books. Its plausibility as a real weapon is disputable, however there are real 10mm pistols available to civilians today. The 10mm Auto round is used for hunting.