Some of the article seems to stem from the book 'Gallyon. Gunmakers of East Anglia' by Richard Gallyon. They took over C.S.Rosson of Norwich. Charles Stanley Rosson was the elder son of Charles Rosson of Derby. I have a particular interest in Derby Gunmakers and am searching for an example of a Rosson gun with this action type. I think very few must have been made. Ver useful photograph and patent drawings. Many thanks. Lagopus.....