Burst of fire from several guns (5)
I believe the answer is:
salvo
'burst of fire from several guns' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for salvo that I've seen before include "Burst of rapid fire" , "Simultaneous discharge of fire" , "Simultaneous discharge of artillery" , "Discharge of weapons in unison" , "Simultaneous firing of weapons" .)