Assault Shotgun (Resident Evil 6)

Town. In the small room on the bridge that requires a partner action to open. When you initially try to access this room you are interrupted by the arrival of the Ogroman. Only appears here if you do not already have this weapon in your possession.

City Hall. Inside the radio room that the J'avo bursts out of as you are proceeding along the corridor from the main hall (and catch a glimpse of Carla). Only appears here if you do not already have this weapon in your possession.

Submarine - Reactor. When you first enter the reactor, proceed through the first room into the hall and down the hatch. The gun is on the workbench on the right-hand side of the room. Only appears here if you do not already have this weapon in your possession.