Conversion Cylinder Replacement Firing Pin
These are hardened replacement firing pins for the conversion cylinder caps. Different conversions do take different sized firing pins. To install a new firing pin in your cap you need to remove the ferrule around it with an appropriate tool and afterwards tighten the ferrule back on it again so that it is "hand tight". If shooting black powder ammunition the firings pins must be removed and cleaned to avoid corrosion. Avoid dry firing with conversion cylinders.