This Remington manufactured late variation receiver insert assembly is for the model 550-1 semi-auto rimfire rifle and is in very good condition with light wear. This late variation assembly consists of the receiver insert, receiver insert spacer, receiver insert spacer pin, cartridge stop detent, cartridge stop detent pin, and cartridge stop detent spring. Early variation insert assemblies were not manufactured to handle the cartridge stop detent assembly. (file photo)

Note: Remington model 550-1 semi-auto rimfire rifles with the following date codes and years of manufacture have been observed with this part:

1949: (KUU) May,  (DUU) September &  (EUU) October

1950: (CWW) April & (EWW) October

1951:

1952: (RYY) November

1953: (PZZ) June 53

1954:

1955: (LB) February & (WB) August

1957: (XD) December

1969: (DS) September