The most likely maker is firm of, John Low Jackson of Nottingham .This company was established in 1821 and ceased to trade in 1914.
The assets and name of the business were aquired by Charles Smith and Son, of Newark-On-Trent, Nottinghamshire.
In the 1970,s I purchased a Jackson Gun from Smith,s and can confirm that it utilised a Westley Richards action.


Roy Hebbes