Hello All,
I follow this site as I collect antique firearms, mostly form the state of Maine. I regularly have a table at the Allentown Forks of the Delaware and usually try to do a display. On October 20, 2019 my display was titled "2 Shot Superimposed Load Lock Mechanisms". In the attached photo, the bottom rifle is a Samuel J. Heston 2 shot superimposed load rifle: 38 caliber, OAL: 50 &1/2 inches and a 35 inch barrel signed in script"S. J. Heston". The lock is marked "Moore, Henszley & Co.", Philadelphia, Pennsylvania lock makers.
Samuel J. Heston, Reading, PA: Gunsmith (1865 – 1870 and Worthington, Indiana from 1882 to 1885).
The top two rifles were made by Hiram. L. Leonard, Bangor, Maine and the third one down is a patented (Ohio 1855) "Daniel B Neal" fowler.
Jerry