Get gun out a bit (6)
I believe the answer is:
nugget
'a bit' is the definition.
(I have seen 'bit of gold' mean 'nugget' so perhaps 'bit' could also mean 'nugget')
'get gun out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'get'+'gun'='getgun'
'getgun' with letters rearranged gives 'NUGGET'.
(Other definitions for nugget that I've seen before include "Scrap of information" , "Maxim perhaps" , "Lump of valuable metal" , "Lump of metal like gold" , "Lump of gold ore" .)