B44 mag, I think Riddle was a lock maker in the 19th century, who sold his locks to gunsmiths. I couldn't find him in my references though I have seen his name on many locks. The gunmaker would sign his name on the top flat of the barrel between the breech and rear sight. Look close as this area gets a lot af wear. Don't shoot that gun without having it thoroughly inspected by a competent gunsmith. They will corrode from the inside out and the drum threads and breech plug threads could be eaten away. I have found many that way....Ed