Hi Dennis,
Bethlehem gunshop records from the mid 1750's include "fitting brass loops to ramrods". Several original 1774 - 75 Oerter rifles carry brass tips at their near bore size muzzle end to protect the rod in loading, plus a long, tapered iron tip at the breech end threaded for a scraper or worm, as Eric and Ron have mentioned. This combination seems to have been tradition in those two shops, and may have carried over from German rifles that often have a horn tip at their muzzle end.
I have not seen records for other shops, so don't know how common or widespread this was. Bob