A gun each (6)

I believe the answer is:

apiece

'each' is the definition.
('apiece' can be a synonym of 'each')

'a gun' is the wordplay.
'gun' becomes 'piece' (piece is a kind of gun).
'a'+'piece'='APIECE'

(Other definitions for apiece that I've seen before include "For or by each one of group" , "Per person" , "A head" , "for everyone" .)

I've seen this clue in The Guardian and The Independent.

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