European town takes little time to track 500 weapons (9)
I believe the answer is:
darmstadt
'european town' is the definition.
(city in Germany)
'little time to track 500 weapons' is the wordplay.
'little' becomes 'tad' (both can mean a small amount).
'time' becomes 't' (abbreviation).
'to track' is a charade indicator (letters next to each other) (some letters follow or go after others).
'500' becomes 'D' (Roman numeral for 500).
'weapons' becomes 'arms' ('arm' can be a synonym of 'weapon').
'tad'+'t'='tadt'
'd'+'arms'='darms'
'tadt' put after 'darms' is 'DARMSTADT'.
'takes' acts as a link.
(Another definition for darmstadt that I've seen is " German city after which element 110 is named".)