in the articles there are a few well known (to us at least) quotes from vegetius, concerning slings, slingers in the roman army, their positioning in the battle-order and a little about balearic slingers.
i'm reading his Epitoma rei militaris now, and i've found a quote that i haven't seen on this site before, so here it is:
in the book II, paragraph 23.
Quote:Archers and slingers would put up a scopae i.e. a bundle of twigs or hay and distanced themselves 600 paces* from the target, so that they could hit their mark more often with the arrow, or at least with the stone from the fustibalus.
...
It's necessary to be accustomed to rotate the sling only once around one's head, when the stone is being cast from it.
*about 178 meters
please take note that i have the materials in croatian, so the clumsiness of the txt is due to my translation, vegetius is not to be blamed because of it