III: Acquire the key or chop down the door with the Axe to open the second floor door in Cabin A to acquire this weapon.
The damage caused by two shots is equal to two swings of a melee weapon, but it will knock the killer down, giving you time to escape. You can also use it to shoot the Gasoline. Using it on the killers will also take off their leg, slowing them down significantly.
IV: An empty one can be found in the gas station. Bullets for it can be found throughout the mansion, including finding 5 in the secret gift room.
Last Christmas: Broken Shotgun