Must be the weather! My neighbour approached me today with a BSA underlever which looks like a very early (1905) BSA/Lincoln Jeffries). Has number 1838 stamped near the trigger block, has bayonet underlever, the trigger guard extends down the stock, stock is walnut/pistol grip.
Has deep etching on cylinder BSA..Lincoln Jeffries etc. Has BSA piled Arms logo rear of rear sight and same logo stamped/etched on the stock. Has a metal butt plate. No blueing left, has been burnished down to bright metal but etching fine. Seems all original with turnwheel on rear sight. I have not chrono'd yet but spring seems lively.
Also has what looks like a patent number stamped just under the rear sight assembly.

Could any of the enthusiasts on this site confirm what I think and then suggest a market value please?

Mike95