Typical lower end Birmingham Hammer gun . Black powder ,Look like steel barrels but can't really tell from the photos. Has it been restored? From the look of the checkering I would say so. Black powder hammer guns were made in Brum well into the 20th C for the export market .As to who actually made it is a matter of guesswork ,and unless you have access to Claybrough's records I doubt you will ever find out.