Many try to turn back shooter (6)
I believe the answer is:
'shooter' is the definition.
(something which shoots)
'many try to turn back' is the wordplay.
'many' becomes 'lot' (I've seen this before).
'try' becomes 'sip' (I've seen this in another clue).
'to turn back' shows that the letters should be reversed in order (I've seen 'turning back' mean this).
'lotsip' backwards is 'PISTOL'.
(Other definitions for pistol that I've seen before include "A small hand-gun", "Shakespearean - weapon", "Type of gun", "Piece", "Arm".)