This weapon's damage, critical damage, and item HP are all double that of a normal BB gun, and its value has been raised accordingly from 36 to 60 caps. In all other aspects it is identical to a normal BB gun.
This weapon can not be found anywhere in the game. It is obtainable only via console command on PC or inventory edit on Xbox 360. To get Black Bart's Bane, use the console command: player.additem 6B535 1