Snowballs, at times (4)
I believe the answer is:
ammo
'snowballs at times' 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 "eg Bullets, shells" , "essential supplies for soldiers" , "that goes in magazine: ...?" , "round" , "Slugs perhaps" .)