Sierra a larger vehicle hit (6)
I believe the answer is:
struck
'hit' is the definition.
(I've seen this before)
'sierra a larger vehicle' is the wordplay.
I cannot really see how this works, but
'sierra' could be 's' (phonetic alphabet: alpha, bravo, charlie etc.) and 's' is present in the answer.
'vehicle' could be 'truck' (truck is a kind of vehicle) and 'truck' is found within the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for struck that I've seen before include "dismantled" , "Hit, knocked with blow" , "Hit as by lightning" , "Made to pause by something unexpected" , "Punched" .)