Ransack to get gun (5)
I believe the answer is:
rifle
I believe this is a double definition.
'ransack' is the first definition.
(rifle can mean to ransack or rob)
'gun' is the second definition.
(I know that rifle is a type of long gun)
'to get' is the link.
(Other definitions for rifle that I've seen before include "Shoulder weapon" , "Sack; firearm" , "Root" , "One that has stock" , "Search and rob for army weapon" .)