Raucous start to squabble over ballistic missile (8)
I believe the answer is:
strident
'raucous' is the definition.
('strident' can be a synonym of 'raucous')
'start to squabble over ballistic missile' is the wordplay.
'start to' suggests taking the first letters.
'over' is a charade indicator (letters next to each other).
'ballistic missile' becomes 'trident' (I've seen this before).
The first letter of 'squabble' is 's'.
's'+'trident'='STRIDENT'
(Other definitions for strident that I've seen before include "ear-piercing" , "Commanding attention" , "Noisy" , "Shrill" , "harsh sound" .)