Shooter uses pins with hesitation (6)
I believe the answer is:
sniper
'shooter' is the definition.
(sniper is a kind of shooter)
'uses pins with hesitation' is the wordplay.
'uses' indicates anagramming the letters (I've seen 'using' mean this (the letters used in a different way)).
'with' says to put letters next to each other.
'hesitation' becomes 'er' (sound made while hesitating - um, er).
'pins' with letters rearranged gives 'snip'.
'snip'+'er'='SNIPER'
(Other definitions for sniper that I've seen before include "He shoots form cover" , "One constantly criticising" , "one who takes pot from a safe place" , "Rifleman firing from concealed location" , "One aiming" .)