As directed, fires rifles (8)
I believe the answer is:
ransacks
'rifles' is the definition.
('ransack' can be a synonym of 'rifle')
'as directed fires' is the wordplay.
'as directed' becomes 'ran' (running is a kind of directing. I am not sure about the 'as' bit.**).
'fires' becomes 'sacks' ('sack' can be a synonym of 'fire').
'ran'+'sacks'='RANSACKS'
(Other definitions for ransacks that I've seen before include "Plunders, loots" , "Searches thoroughly, causing damage" , "Takes as spoils" , "Rifles" , "Pillages or searches roughly" .)