Could that be an 1874 Sharps? The later 1877 had a few changes including the hammer. That looks to be transition time-my guess may be off. Ihave an original 1885 HW Winchester in 45-60 made in 1887.
Also own a Shiloh No1 1874 in 45-70 with Axtell Mid Range-30 inch full octagon barrel. Google up C. Sharps serial numbers for a response.
"The credit belongs to the man who is actually in the arena-not the critic"-T. Roosevelt There are no atheists in fox holes or in the open doors of a para's aircraft.....