Unruly mob in Shakespeare use guns (7)
I believe the answer is:
Here is my best explanation:
'use guns' is the definition.
'unruly mob in shakespeare' is the wordplay.
'unruly' indicates anagramming the letters.
'in' means one lot of letters goes inside another.
'shakespeare' becomes 'bard' (I've seen this before).
'mob' with letters rearranged gives 'omb'.
'omb' inserted inside 'bard' is 'BOMBARD'.
(Other definitions for bombard that I've seen before include "Attack persistently", "not working? Keep hitting", "Organ stop", "Attack with missiles", "Batter heavily and persistently" and "Pelt with missiles".)