T/C makes the Black Mountain Magnum in a 12ga shotgun. Cat#5038 Blue'd barrel W/Advantage Timber Camo stock.
Knight also makes the TK2000, but this is an inline shotgun.
If you're looking for a used 12ga. blackpowder shotgun, I have a T/C New Englander, Blue'd barrel, Synthetic stock, with an adjustable choke tube for sale. It's like new and I have several chokes tubes that would go with the shotgun. $200
I can send you .jpg pic's if you're interested or I can be reached at [email protected]
Keep it in the 10X
Mac454