Contest for gun-runners? (4,4)
I believe the answer is:
arms race
'contest' is the definition.
(arms race is a kind of contest)
'gun-runners?' is the wordplay.
I cannot really understand how this works, but
'gun' could be 'arm' (I've seen this in other clues) and 'arm' is located in the answer.
This explanation may well be incorrect...
'for' acts as a link.
Can you help me to learn more?
(Other definitions for arms race that I've seen before include "A hostile international competition" , "Potentially dangerous competition" , "military competition" , "dangerous situation escalating" , "Weaponry competition" .)