Old characters try rolls with meat (5)
I believe the answer is:
ogham
'old characters' is the definition.
(I've seen this before)
'try rolls with meat' is the wordplay.
'try' becomes 'go' (both can mean an attempt).
'rolls' is a reversal indicator (I've seen 'rolling' mean this).
'with' is a charade indicator (letters next to each other).
'meat' becomes 'ham' (ham is a kind of meat).
'go' reversed gives 'og'.
'og'+'ham'='OGHAM'
(Other definitions for ogham that I've seen before include "Ancient British alphabet" , "Old Irish writing system of lines and notches in stone" , "Old Irish alphabet with letters of lines and notches" , "Old Celtic alphabet" , "Old Irish writing of carved lines and notches" .)