This is the breech pin base extension also called the firing pin Winchester 1873 .22 caliber rifle. The breech bolt and firing pin is different in the .22 as compared to the other calibers of the 1873 lever-action rifles. This rod is attached to the breech bolt by a pin (part number wp626-b) The hammer strikes this rod and pushes the breech bolt into the cartridge. A projection on the face of the bolt is what strikes the cartridge and ignites the round.
