Here is a fine B.S.A Improved model D that made its way to Canada. It features a straight hand stock, and has the second pattern bayonet cocking lever with strengthening fillets. It also features a BSA no.12 peep sight mounted into a milled out section of the trigger block. It has a number 10 rearsight, and so these attributes date this gun during the period early 1908 (serial number approx 19000) to October 1911 , when the side button cocking lever was introduced.
photo courtesy of Murray Gardner