Out of range of French explosive device (7)
I believe the answer is:
grenade
'explosive device' is the definition.
(grenade is a type of explosive)
'out of range of french' is the wordplay.
'out of' is an anagram indicator.
'of french' becomes 'de' ('of' in French).
'range' is an anagram of 'grena'.
'grena'+'de'='GRENADE'
(Other definitions for grenade that I've seen before include "Enraged (anag)" , "ultimate weapon" , "Handy bomb" , "One might go off" , "Hand-thrown explosive" .)