This Remington manufactured late variation breech block assembly is the for the model 121 slide action rimfire rifle in 22 S, L & LR caliber and is in very good condition with light wear and some specks of rust staining. This breech block assembly consists of the late variation breech block, round type firing pin assembly and the late variation extractor assembly.  (file photo)

Note: Model 121 rimfire rifles with the following serial numbers have been observed with this part: 64734, 108148, 162751 & 164006.