I have been offered a break action single with Jones underlever in .500 express 3".

The barrel is marked "Converted by J.Coster, Edinburgh" with no other markings. The rifle has a 30" barrel with little finish, a good bore except fo the last inch at the muzzle. It was probably a muzzle loader, has a very long top tang, good walnut & was probably a very nice gun in it's day.

Julius Coster worked for Alex Henry for a while & that's about as much as I know.

Anyone have any thoghts on this one?

Photos will come if I buy it.