Dug a couple more buttons and a round ball of what I am assuming is cast lead or lead alloy (VDI +48). (The dime is just for comparison, did not dig that today).
Poking around the net it looks like other pictures of musket balls I saw, but seems a wee bit small? (about .55 inches). If it isn't a musket ball, not sure what it is . No Revolutionary War battles near this site that I am aware of, so who knows?