Daryl, thanks for the suggestion. They accepted my buy it now lower offer and the set is on the way. I also added the first two volumes of The British Shotgun as SKB suggested. Ends up that I already had the third volume on hand. Must have been in a large lot of books I bought out of an estate a few years ago or one I just bought off EBay and not needing it now, just put it into the gun book library.
Most of my interest for now I guess would be in the 1870-1890 era. There seems to have been a never ending stream of alterations, improvement and schemes trying to get around other patents. Most failed, some just were not desired, some were quickly replaced by other new improvements to the design. Trying to sell the latest and greatest, to a limited clientele, year after year must have been one driving force. If you want your regular customer to buy another gun you need to show him how the newer model has improved or addressed some detail lacking in his current gun. If you made perfect light bulbs, which never burned out and were for ever state of the art, you would soon go out of business. But if you had an new and improved version to sell every time your last one burned out or if you had a brighter bulb than the last one you would be around for a long time.