Pub tantrum brings artillery onslaught (7)
I believe the answer is:
barrage
'artillery onslaught' is the definition.
(I've seen this in another clue)
'pub tantrum' is the wordplay.
'pub' becomes 'bar' (both are drinking establishments).
'tantrum' becomes 'rage' (I've seen this in another clue).
'bar'+'rage'='BARRAGE'
'brings' acts as a link.
(Other definitions for barrage that I've seen before include "Concentrated artillery bombardment" , "Heavy gunfire" , "Sustained attack - means of damming river" , "Deterrent to low-flying air attacks" , "Heavy, continuous fire" .)