This Marlin manufactured early variation breech bolt assembly with style No. 7 striker knob (thick rim) is for the model 25 bolt action rimfire rifle and is in very good condition with light wear. In the early variation bolt assembly the firing pin is located directly below the cartridge guide spring groove.  If disassembled the breech bolt rear measures approx. 4.070" long and this breech bolt front is shorter in length than the late variation breech bolt front. (file photo)

Note: Marlin model 25 rimfire rifles with the following year/serial number have been observed with this part:

1983: 17670346

1984: 16681928 & 16719503

1986: 14654568 & 14668133