When duds explode at certain points, its surprising (6)
I believe the answer is:
sudden
'surprising' is the definition.
(similar in meaning)
'when duds explode at certain points' is the wordplay.
'when' becomes 'e' (I've seen this in other clues).
'explode' indicates an anagram.
'at' is a charade indicator (letters next to each other).
'certain points' becomes 'n' (I can't explain this - if you can you should believe this answer much more).
'e'+'duds'='eduds'
'eduds' with letters rearranged gives 'sudde'.
'sudde'+'n'='SUDDEN'
'its' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for sudden that I've seen before include "Occurring quickly without warning" , "Swift" , "Quickly, without notice or warning" , "Happening abruptly" , "Occurring unexpectedly quickly" .)