Rocket design India managed to finish early (10)
I believe the answer is:
projectile
'rocket' is the definition.
(I know that rocket can be written as projectile)
'design india managed to finish early' is the wordplay.
'design' becomes 'project' (synonyms).
'india' becomes 'i' (phonetic alphabet: alpha, bravo, charlie etc.).
'managed' becomes 'led' (I've seen this in another clue).
'to finish early' means to remove the last letter (the letter comes to an end before its last letter).
'led' with its final letter taken away is 'le'.
'project'+'i'+'le'='PROJECTILE'
(Other definitions for projectile that I've seen before include "shot?" , "Missile" , "Ball" , "Something launched" .)