Very effective at short range, each shot produces 10 pellets. This modern shotgun uses a unique rotary magazine system. The magazine holds 6 rounds by default, and with mods can hold up to 12. The Widowmaker has three Picatinny accessory rails, mounting a standard iron sight on the top rail.
This weapon is obviously inspired by the SRM Arms M1216 shotgun; specifically, the 10-inch barrel 1208 model with an 8-round magazine.
This weapon was ported into Team Fortress 2 as a promotion weapon for the Engineer class, where it does not need to reload and instead, uses the Engineer's metal for ammo, consuming 30 metal with each shot and returning metal equivalent to the amount of damage, it lacks the front grip that is standard with the weapon and is a bit more cartoonish in the Team Fortress 2 incarnation.
Early information suggested that the shotgun would have the option of firing "special anti-mech rounds". Presumably, at one stage it was planned for the game to feature multiple ammunition types for each weapon, but in the final game the shotgun can only use buckshot rounds.