Info on a percussion double barrel shotgun ...

[rfd]

Found at an estate sale, don't have a clue what it is or its value, "Sylvester Steel Lock"? ...

https://i.imgur.com/4fp8Urx.jpg

https://i.imgur.com/4ro2zws.jpg

https://i.imgur.com/eKWcubV.jpg

https://i.imgur.com/PB51do7.jpg

https://i.imgur.com/S9dUQJ3.jpg

https://i.imgur.com/bW0qTff.jpg

[FrontierMuzzleloading]

remove the barrel and look under it for stamping of either english or belgium proofing marks.

[rfd]

https://i.imgur.com/udoLQdi.jpg

[pietro]

.

The proof marks appear to indicate a Birmingham (England/Britain) Proof House definitive black powder proof for shotguns.

"CB" may be a maker's mark, but IDK who.

.

[kaiser]

Nice old "piece", that if from Birmingham would place it somewhere around the 1850's. I have a "Cape" gun that is 12x.45 cal (BP) with similar markings. Do you intend on firing it? If you do, I would recommend FFg (only) black powder with a starting load around 50gr with a 1 oz or less of shot for "starters". Look up Birmingham firearms; it tells of a pretty interest history of the company. Congrats on your find.