Brexiter insulted loads empty gun with bullets (6)
I believe the answer is:
gammon
'brexiter insulted' is the definition.
(insult referring to a Brexit voter)
'empty gun with bullets' is the wordplay.
'empty' means to remove the middle letters.
'with' is an insertion indicator.
'bullets' becomes 'ammo' (I've seen this before).
'gun' with its centre removed is 'gn'.
'gn' placed around 'ammo' is 'GAMMON'.
'loads' is the link.
This may not be right. It may be part of another bit of the clue.
(Other definitions for gammon that I've seen before include "Cured or smoked ham" , "Hoax - hock of hog" , "bit of a swine" , "Cured meat of hindquarters of a pig" , "Cured ham; nonsense" .)