This lead sphere may have been a musket ball and, if so, it has probably been fired as embedded in its surface is a thin strip of silvery metal. However, the strip of metal may have been deliberately inserted when the object was made, and it may once have been longer with, perhaps a hole from which it could be hung, as a weight.
As always, if you can tell at a glance what this unknown object was, don't hesitate to get in touch.