I built my Hawken pistol with the captured steel rod as per the pair of originals in Baird's first book. The rod is 1/4" dia. is 'upset' slightly on the inner end to prevent loss, and has a large bulbous brass button at the muzzle. This pistol is .60 cal. and this little steel rod works just fine, not only for loading, but for cleaning the barrel too. The brass button is just the right size to act as a jag for cleaning. Obviously, the rod doesn't have a collar to centre it in the bore, but I have experienced zero appreciable wear at the muzzle from the rod in over 35 years of use.