Hero putting bullets into FBI agent? (7,3)
I believe the answer is:
leading man
'hero' is the definition.
(thesaurus)
'bullets into fbi agent?' is the wordplay.
'bullets' becomes 'lead' (I've seen this in other clues).
'into' becomes 'in'.
'fbi agent?' becomes 'gman' ('G-man' can be a synonym of 'fbi agent').
'lead'+'in'+'gman'='LEADING MAN'
'putting' is the link.
(Other definitions for leading man that I've seen before include "top fellow on stage" , "Principal actor" , "megastar?" , "Protagonist" , "Star" .)