Does some striking when the boom returns (4)
I believe the answer is:
raps
'does some striking' is the definition.
I can't tell whether this defines the answer.
'the boom returns' is the wordplay.
'the boom' becomes 'spar' (I've seen this in another clue).
'returns' is a reversal indicator.
'spar' backwards is 'RAPS'.
'when' is the link.
Can you help me to learn more?
(Other definitions for raps that I've seen before include "Knocks sharply" , "'Knocks, on the door say (4)'" , "Sprechgesang pop hits" , "Cracks" .)