It appears to be an original US M1816/22 musket with new made barrel by a top maker, nothing "fantasy" about it except for the severe stock modification. Mr. Large would make an exact exterior duplicate of a barrel - rifled or smooth bore in any caliber - if you would send him your barrel - a drop in replacement so that you could have an interchangeable new barrel to use in your original musket. I had a 45 or so minute conversation with him on this subject back in the late 1980s and he was very friendly. I enjoyed the conversation, even after receiving the phone bill. Too bad the original barrel wasn't included in your purchase.