Long-barrelled gun (5)
I believe the answer is:
rifle
'long-barrelled gun' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for rifle that I've seen before include "shoot?" , "Gun - steal" , "Ransack; a weapon" , "Plunder - ransack" , "Long-barrelled weapon, normal army equipment" .)