Doug,
That sounds like an interesting project. Regarding the rifle, Mr. Gallien's comments pretty well summarize whatever could be gleaned from the photos. He is a recognized authority on the topic. I can only add that the rifle (now evidently a smoothbore) appears to be in remarkably good condition, and it was also stocked with a very nice piece of maple. By all means, try to get your hands on it when you travel to Kansas, take more photos and lots of measurements.
This topic interests me. If you don't mind sharing the name of your buffalo-hunting ancestor, I'll try to look him up. Send a private message if you have reservations about posting his name here. There is a series entitled
The Encyclopedia of Buffalo Hunters and Skinners which will list names and biographies of all the hunters and skinners the authors can find documented, but they are listed alphabetically and the series appears to have stalled out with Volume 2, up through surnames beginning with "K." If your ancestor's surname starts with the letters A through K, he may be in there. Or maybe not. There are a few omissions.
In addition, I would highly recommend that you get your hands on a book entitled
Hunting and Trading on the Great Plains, 1859-1875, by James R. Mead. The author was a professional hunter who also engaged in trading with the native people. During the period covered by this book, he was shooting round-ball muzzleloaders. His book is an extraordinary document, very easy to read and thoroughly engaging. Mead was very observant and highly literate. His writing was originally published in the
Transactions of the Kansas State Historical Society, but the papers were assembled and edited by his grandson, Schuyler Jones, who is himself a well respected historian. The book was first published by the University of Oklahoma Press:
It was more recently updated and re-edited by Dr. Jones, and re-published by Rowfant Publishing:
Both editions are unfortunately out of print at this time, but you might find one on the used book market online, and I think
Al's Old & New Books in Wichita may have a few new copies of the Rowfant edition.
In any event, good luck with your research!
Notchy Bob