After shooter's turned up, acquire piece (6)
I believe the answer is:
nugget
'piece' is the definition.
(nugget is a kind of piece)
'after shooter's turned up acquire' is the wordplay.
'after' means one lot of letters go next to another.
'shooter' becomes 'gun' (I've seen this before).
'turned up' shows that the letters should be reversed in order.
'acquire' becomes 'get' ('get' can be a synonym of 'acquire').
'gun' written backwards gives 'nug'.
'nug' put next to 'get' is 'NUGGET'.
(Other definitions for nugget that I've seen before include "bit of gold" , "valuable piece of information" , "Scrap of information" , "(Small) lump (of value)" , "Lump (of gold, etc)" .)