A shotgun, also called a "scattergun," is a firearm designed to shoot a multitude of lead or steel balls of varying sizes, greatly increasing the weapon's hit potential. This makes it very effective at hunting game. However, the accuracy and power found at close range starts to diminish as the target gets farther away. Shotguns designed for the military's use are often called "combat shotguns."
The WinchesterWidowmaker shotgun is a double-barreled 12 gauge shotgun with a mahogany grip. It also has a sawed-off variant in Fallout 2. It is a common weapon used early in the game. Compared to the sawed-off version, this has a 2-point-lower max damage, and requires both hands, but has doubled range.
The following is based on unverified behind the scenes information and has not been confirmed by canon sources.
The shotgun's name, the Winchester Widowmaker, appears to be a reference to the real life Winchester Model 1911 shotgun that was nicknamed "the Widowmaker" due to a safety issue. Unlike the real shotgun, however, the Widowmaker in the games is a double-barrel shotgun instead of a single-barreled semi-automatic.
End of information based on unverified behind the scenes information.