jdm,
Thanks for the photo. Could you also post the lock side of the Young rifle?
Bob, Thank you as well for the photos of the flintlock.
My interest in the right screw lock started when I began to obtain some of the Oxford County rifles from Dwight Demeritt whom I knew quite well. ( Unfortunately, Dwight passed away at age 90 in January, 2019). Although he found a few guns with the right screw lock from makers outside of Maine, he concluded that most of that style were made by Richard Houghton (about 20 known), Abel Spalding (1 known), Loren Wrisley (2 known) and Deploria Bisbee (3 known), the Oxford County gunsmiths. That county was the only place in Maine where Kentucky style rifles were made. A Richard Houghton is pictured below purchased from Amoskeag Auctions.
Question remains: who was J. F. Medcalf? Thank you all for your responses.
Jerry