A bulk distribution of capital (5)
I believe the answer is:
kabul
'capital' is the definition.
(capital of Afghanistan)
'a bulk distribution' is the wordplay.
'distribution' indicates an anagram.
'a'+'bulk'='abulk'
'abulk' with letters rearranged gives 'KABUL'.
'of' acts as a link.
(Other definitions for kabul that I've seen before include "Middle Eastern capital" , "Afghan city" , "Move through water" , "city abroad" , "Capital city of Afghanistan" .)