There is a book by Art Phelps, "The Story of Merwin, Hulbert & Co." Its out of print, so you have to do a search on e-bay or some other sellers & buyers auction sites. It may not have all the answers but can give a approxamation to when certain models were made. The dates above are correct 1876-1891, the company was in operation. I can only tell if a full size or belt revolver is a early, mid, or late model. Its like the earliest models were open tops (no top-straps) were single action only up in till 1879 and could only be had with 7" barrels, available only in .44 caliber. By 1881 the company came out with the "Pocket Army" which had the parrot-beak or skull-crusher grip. By 1882, the top-strap was added from there after all revolvers had them. By late fall of 1882 they added the double actions to their offerings. By the fall of 1883 the company offered the more desirable 44-40 to their already .44 Merwin&Hulbert cartridge (similar to the .44 Colt which was a heel-based bullet) This information in bold, was found in the book "Firearms of the American West" Information I have remembered over the years fact or not, you be the judge. Heres what I believe to be right; The earliest had an extra screw in the side of the frame below the cylinder which was an access plate for cleaning. Generally these were considered 1st year productions or 1st model. This was discontinued due to no government or Army contracts, so without side-plates are considered 2nd models. Scooped fluted cylinders ended sometime shortly after the top-strap was added, but some still had them as the didn't let them go to waste. Top-straped versions are considered 3rd models, and the final version 4th model had a rib on the top of the barrel, like the S&W Scholfield. I hope some will either agree or correct my memory. LM
