Gunmen, note, get rid of loot (7)
I believe the answer is:
ransack
'loot' is the definition.
(I know that loot can be written as ransack)
'gunmen note get rid of' is the wordplay.
'gunmen' becomes 'RA' (Royal Artillery).
'note' becomes 'n' (abbreviation).
'get rid of' becomes 'sack' (as in sacking a worker).
'ra'+'n'+'sack'='RANSACK'
(Other definitions for ransack that I've seen before include "Go through a place causing damage and stealing things" , "Search thoroughly and roughly" , "Plunder - rummage" , "Rummage, rifle" , "Examine thoroughly" .)