M1897 Shotgun (Bureau)

The Winchester Model 1897, known as the first truly effective pump-action shotgun, is a 12-gauge shotgun with low accuracy more suited for close-range combat than any attempt to snipe from afar.

It can be first accuired in Groom Range, near the elevator in the hangar leading to the Elerium labratories, near the first intance you can take grenades.