Munitions, for short (4)
I believe the answer is:
ammo
'munitions for short' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ammo that I've seen before include "Slugs perhaps" , "Bullets, etc. (colloq.)" , "Shot" , "Bullets (sl.)" , "Projectiles" .)