"Rix Fr 13
Bronze cylinder, Casalbordino:
a b g d v z ḥ [i] k
Aside from 〈a〉, all the letters are/can be consonantal, without regard for voicing."
It's a bronze cylinder, found at Casalbordino in Abruzzo, now in the Museo Nazionale in Chieti.
The letters that accompany what were originally ten holes evenly-spaced around the cylinder therefore indicate intervals of 36 degrees up to 324 (360 and 0 being of course the same). This division would give the artillerist a chance to adjust the tension with some degree of regularity, based on prior experience (probably the previous shot!). The cylinder probably dates to the period of the Social Wars, ca. 90 BCE, when many of the Italic tribes took arms against Roman hegemony.