Be ahead with heavy metal (4)
I believe the answer is:
lead
This might be a double definition.
'be ahead' is the first definition.
'lead' can be an answer for 'be' (leading is a kind of being). I am not certain of the 'ahead' bit.
'heavy metal' is the second definition.
(lead is a heavy metal)
'with' is the link.
Can you help me to learn more?
(Other definitions for lead that I've seen before include "First put down spade, say" , "in first place" , "Guide; graphite" , "Guide,direct" , "pioneer" .)