This Remington manufactured early variation rear receiver insert has the two "threaded" holes on the underside designed to attach the early variation two hole magazine lock using two machined screws. This rear receiver insert is for the early model 513-T Matchmaster bolt action rimfire rifle and is in very good condition with light wear. (file photo)

Note: Remington model 513-T Matchmaster bolt action rimfire rifles with the following serial numbers have been observed with this part: 48628, 72972, 73329 & 77432