This Remington manufactured third variation carrier is for the model 12-CS slide action rimfire rifle in 22 Rem. Special caliber and is in very good condition with light wear.  (file photo)

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

12-CS: 225240

Personally, I am seeing absolutely no difference between the 22 LR carrier and the 22 Rem Special carrier when comparing both 3rd variation parts side by side