The combat shotgun was a weapon born out of necessity in a world ravaged by war and resource shortages. Instead of lightweight metal alloys used in eg. the Citykiller, it uses wood and stamped metal sheets that greatly reduce manufacturing costs, while its design maximizes durability without sacrificing the firepower provided by standard 12 gauge shotgun shells. Although it might have seemed antiquated, the combination of firepower, ruggedness, and low price tag resulted in widespread adoption by the United States military. Though early models used a combination drum-and-tube magazine (when placed in the magazine well, the drum would fill the tube with shells), standardized, mass-produced versions used a more conventional magazine placement with a variety of magazine types available.
Its widespread use led to the development of a large variety of modifications, allowing for in-depth customization. These include various optics, ranging from simple iron sight rings, through reflex sights, to night vision and recon scopes, bayonets and compensators, as well as adjustable, pistol-grip tactical stocks from lightweight alloys. To capitalize on this, the military introduced the combat rifle: A combat shotgun rechambered for rifle rounds and without the heat shroud protecting the barrel. Everything else was left in place, including the original magazine well with the drum mount. Despite that, the resulting rifle was as cheap, effective, and popular as the combat shotgun.
Its popularity proved enduring, as working units were salvaged after the Great War and pressed into use by wastelanders of all stripes, including merchant guards, adventurers, raiders, slavers, Gunners, and Talon Company mercs.
Vastly superior to the sawed-off shotgun, the combat shotgun combines a large magazine with mutilating close-range damage. The only drawback is the weapon's poor reliability, as the combat shotgun deteriorates quickly. However, considering it is commonly used by human opponents, and its use in traps, you can usually find enough to keep at least one in fully working order.
Unlike the combat shotguns in previous Fallout games, the combat shotgun in Fallout 3 is not fully-automatic.
At 100% condition the combat shotgun can fire 145 shells, approximately 12 drum magazines, before breaking.
The Terrible Shotgun, a shotgun that deals an obscene amount of damage to targets, in exchange for a much wider spread.
Sim version (Operation: Anchorageadd-on), a sim-only version of the weapon which differs in health, having such a high rating as to be essentially non-degrading. It also has a cleaner, less battered appearance than the standard Capital Wasteland version.