they are spherical lead bullets the same weight as most roman sling glandes.
Given that they didn't have muskets or elastic powered hand catapults, the they were either thrown with slings or some kind of ballista/mangonel. Which the romans definitely did have.
Also given that the roman did actually train and drill groups of slingers - it's a good bet most,if not all of those bullets were thrown by slings.
Quote:He is one of the guys u want to be friend with... when the zombies come around
I'll second that
Though, these days, I'm thinking more russians than zombies