Andrew Nethercott Antiques has dated this piece to the 1800s.
The lock plates with inscribed monograms, worn, looks like RW perhaps for Robert Wheeler
The rib between the barrels engraved London

The steel with high quality engraving and numerous decorative features throughout.
Powerful hammer spring cocks to two positions and spring frizzen.
Lightly browned barrels, dark etched ironwork.
Fine cross grained walnut stock with some possible small old repairs under the barrels.
Rings to attach shoulder strap.
Non original part ram rod.
All in very good sound condition.
Internal diameter at the muzzle 1/2"
Barrel length 16"
Overall length 30,3/4"
Weight 1228 grams.
Andrew Nethercott Antiques has dated this piece to the 1800s.
Works of art, collectables, scientific and decorative antiques from the 17th - 20th century
You can view the stock and full dealer information on the Andrew Nethercott Antiques Profile Page