I am working on an Underhammer Shotgun using a Billinghurst Action from MBS and a Colerain Barrel. I may use the gun in a competition which requires that the gun be a replica of period shotgun. I have seen a number of examples of Billinghurst Shotgun/Rifle combinations. However, I have not been able to find a picture of a Billinghurst Underhammer with a smooth bore.
Does anyone have pictures of a smoothbore Billinghurst style gun?