I would be thrilled to find one - attached to the musket still...!
I've only found like seven or eight round balls before, so recovering gun parts
or the ENTIRE weapon, is still possible....!
Best way I have found those is on archaeological digs. Sifting everything around old fort/camp sights turns up many things missed by a detector. It always fascinates me the number of metal items that are found by sifting , even though the site has been hammered by detectorists for many years.