Longarm-something a little different 2

[debnal]

Here is another "big" gun. It has a 47 inch 100 caliber barrel! Shown with two Rev War fowlers for scale.  The breech is just over 1 3/4 inches and the butt is 2 3/4 inches. Lock marked Ketland & Co in script, British proofs and London on barrel. Tang carving is a little different than I would expect on an English gun. This one looks and feels more like a market/waterfowling gun to me. any help on this would be appreciated.
Al