Magazine's cold insolence (4)
I believe the answer is:
clip
'magazine's' is the definition.
(clip can mean a magazine of ammunition in a gun)
'cold insolence' is the wordplay.
'cold' becomes 'C' (eg on taps).
'insolence' becomes 'lip' (I've seen this in another clue).
'c'+'lip'='CLIP'
(Other definitions for clip that I've seen before include "Device for holding papers together" , "Trim; film extract" , "Film extract; light blow" , "speed" , "Cut, trim" .)