Bullet belt (4)

I believe the answer is:

slug

I believe this is a double definition.

'bullet' is the first definition.
('slug' can be a synonym of 'bullet')

'belt' is the second definition.
(thesaurus)

(Other definitions for slug that I've seen before include "Bullet; swig" , "gulp!" , "Slimy fellow in bed" , "Bullet - punch" , "Wallop" .)

I've seen this clue in The Independent.

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