Howdy Again
Dispatch from the Learn Something New Every Day Department.
I was not aware of the Richards Transitional model, even though I have the McDowell book on conversions, the most authoritative book on the subject. Just did not take the time to read the entire chapter on Richards Conversions. Mea Culpa.
According to 'A Study of Colt Conversions and Other Percussion Revolvers', by R. Bruce McDowell, "All Second Model Richards are rare because of the limited number produced". I have not found a chart anywhere in the book that says exactly how many were made, but one can assume they are more rare than the 1st Model. Hence, ignore my earlier $2500 statement, I have no idea what it is worth.
However, beware that counterfeiting rare guns has always been a profitable business. Have it checked out in person by an expert before trying to determine the value.
Regarding Patent Markings: McDowell says " The two line patent dates,-PAT.JULY.25.1871-/-PAT.JULY.2.1872- is the predominant frame stamping for this particular model....These patent dates are sometimes over an earlier COLTS/PATENT stamping....The two-line patent dates are sometimes stamped with dashes at the beginning and end of each line and other times without dashes."
For reference only, this is the patent stamping on my 1st Model Richards Conversion.
That's the best I can do.
P.S. In the future please size your photos down before posting them. They are so big that one has to scroll back and forth to view them.
Too bad somebody gouged the dickens out of the pair of screw holes on the backstrap.