ZULU is correct. Several gunmakers in Belgium and France would take old worn out surplus military muzzle loading muskets and convert them to a breech loading single shot shotguns by cutting off the breech end of the gun and fitting some sort of side swinging breech block and boring out the barrel to a shotgun gauge. They would also bend the hammer over to strike the new firing pin. These guns were originally intended to be sold to natives in Africa hence the ZULU name. Of course they made it to the United States where they sold for as little as $3,00 each.