Discharge of firearms consisting of fine lead shot (8)
I believe the answer is:
enfilade
'discharge of firearms' is the definition.
(volley of bullets)
'fine lead shot' is the wordplay.
'shot' indicates anagramming the letters.
'fine'+'lead'='finelead'
'finelead' with letters rearranged gives 'ENFILADE'.
'consisting of' is the link.
(Other definitions for enfilade that I've seen before include "Gunfire from the flanks" , "Salvo of shots" , "Fire along whole line" , "A lot of shots in a row" .)