Watch List notes:

Lead sling bullet with the name of Gnaeus Pompeius Jr. (son of Pompey). Roman, circa mid 1st century BC. Biconical sling bullet inscribed CN MAG / IMP (for Gnaeus Magnus Imperator). Length: 39mm. Light scrape. Intact and rare. CIL II 4965.

Such sling ballistas have been found in Spain and are generally associated with Pompey's war against Caesar, particularly the Battle of Munda (March 45 BC).