This Remington manufactured open (rear) sight leaf is for the model 510 Targetmaster bolt action rimfire rifle and is in very good condition with some light surface rust specks.  (file photo)

Note: Remington model 510 Targetmaster rifles with the following date codes (month and year of manufacture) have been observed with this part: PH (June 1939), LJ (February 1940), PJ (June 1940), EK (October 1941), LL (February 1942), CL (April 1942), OL (July 1942), ESS (Oct. 1947) , & AC (March 1956).