Friend in possession of revolutionary weapon (7)
I believe the answer is:
machete
'weapon' is the definition.
(machete is a kind of weapon)
'friend in possession of revolutionary' is the wordplay.
'friend' becomes 'mate' (mate is a kind of friend).
'in possession of' is an insertion indicator (has inside).
'revolutionary' becomes 'Che' (Che Guevara the Marxist revolutionary).
'mate' enclosing 'che' is 'MACHETE'.
(Other definitions for machete that I've seen before include "Broad heavy knife used in S American jungles" , "Broad heavy knife common in Central America" , "Heavy knife used as weapon" , "cutter" , "The mace (anag.)" .)