Base emptied turret during explosion (6)
I believe the answer is:
bottom
'base' is the definition.
(I've seen this before)
'emptied turret during explosion' is the wordplay.
'emptied' means to remove the middle letters.
'during' means one lot of letters goes inside another.
'explosion' becomes 'boom'.
'turret' with its centre removed is 'tt'.
'tt' inserted into 'boom' is 'BOTTOM'.
(Other definitions for bottom that I've seen before include "Quark's flavour" , "Lowest part of anything" , "Least successful position" , "Base; Shakespearean character" , "Lowest part or underside" .)