I pre-ordered Bioshock Infinite from GameStop, and forgot about entering the code to get the Comstock China Broom shotgun. I'm wondering how you obtain this weapon. Does it appear in the vending machines, or do you pick it up from the environment?
Find the China Broom shotgun that comes with the GameStop pre-ordered version
bioshock-infinite
Related Solutions
The key unlocks a chest in a house called the "Lansdowne Residence." You'll find this location from backtracking out of the Order of the Raven, over a skyhook grapple point, and through either a double doors or a skylight into a bedroom.
From the bedroom, go down two flights of stairs to the middle level. There's another bedroom and a bathroom on this floor, and the chest is in the bedroom.
In the chest is a salt recovery item and an infusion. There's also a voxophone in the room which explains why the chest (but not the key) is in the house.
Well, not directly, so don't worry about it.
The point here is that you made a choice that you will remember and notice it later on.
More information with SPOILERS, read only AFTER FINISHING THE GAME:
Thanks to this choice you will almost immediately notice that the girl at the end is not Elizabeth since she doesn't have the brooch you selected for her. It was a nice touch by the game creators.
Best Answer
The "China Broom" Shotgun is the standard shotgun in the game, and there's nothing special you have to do to find it. You'll find enemies carrying throughout the game.
The GameStop preorder bonus is a special skin and "damage enhancement" for this weapon, which has stars down the side of the barrel. Whenever Booker picks up a shotgun, it should get these unique benefits.