Firing pin retaining pin .22 cal Winchester 1873

This is the pin that holds the Winchester 1873 .22 cal firing pin, or piston to the breech bolt. The firing pin set up was different on the .22 cals compared to the other calibers. It used a rod or piston that was pinned to the breech bolt. A projection on the left side of the breech bolt face is what struck the rim of the cartridge. This retaining pin should fit tightly in the breech bolt but loosely in the Piston, which is also called the breech base extension. See picture below for location.