This Remington manufactured late variation rear receiver insert is for the later model 511 Scoremaster bolt action rimfire rifle which uses the one hole magazine lock that mounts to the inside recess of the stock and not the receiver insert. This receiver insert is in very good condition with light wear. (file photo)

Note: Firearms with the following date codes have been observed with this part: PTT (June 1948), XTT (Dec. 1948), EUU (Oct. 1949), CWW (April 1950), EWW (October 1950), OYY (July 1952), WYY (Aug. 1952), BZZ (January 1953), KZZ (may 1953), ED (October 1957), KE (May 1958) & XE (Dec. 1958).