I recently dug up what looks very much like a civil-war era mini ball slug.It was in an area that has a lot of civil war history, but I don't know if it is authentic or if someone was in the area doing some blackpowder hunting. It was down about 7" or so in a new (3yrs. old) lawn. Anybody have any suggestions as to how to date it, or an email address of someone who can help?