These photographs were taken in 1989 by an unknown English photographer that I hired through Mr. Brian Nodes, Administrator of Blair Castle, Perthshire, England.
The rifle first came to my attention in an article by John R. Elting titled simply An American Rifle. Unfortunately I do not have the publication information on that article. Mr. Elting gave these measurements: overall 58.5 inches; barrel 42.5 inches, .54 caliber, seven furrow rifling.
John Nicholson had a shop on Front Street near the drawbridge in Philadelphia. He advertised in the Pennsylvania Journal in 1781 (See Early American Gunsmiths, 1650-1850 by Henry J. Kauffman; 1952.
I believe the rifle is miss-cataloged in the castle collection. They have it listed as part of a collection sent back to England by Captain George Murray in 1768 or 1769. I believe the rifle dates closer to 1785-90. The pointer engraved on the patchbox door may be a later addition after the rifle was in England.