"Legends of the Fall" has one maybe two double rifles.

One is carried by the Brad Pitt character ivory hunting, and from the cartridges is supposed to be a bore cartridge I think. From the bandolier he wears in the hunting camp.

The other is a gift to his father Ludlow, but it may be a shotgun.

Haven't gone back to see if it has already been mentioned. Added it here for my own future benefit