This Remington manufactured early variation cartridge stop is the model 12 slide action rimfire rifle in 22 S, L, & LR caliber which is using the first or second variation action bar. This part is in very good condition with light wear.  (file photo)

Note: Remington model 12 takedown slide action rimfire rifles with the following serial numbers have been observed with this part: 351695

12-A: 30310, 100823 & 374065

12-C: 229853, 303506, 408616, 409187, 597770, 600364 & 640490