Ceremonial firing of guns (6)
I believe the answer is:
salute
'ceremonial firing of guns' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for salute that I've seen before include "Bring hand smartly to cap" , "Hail, greet" , "Acknowledge (superior)" , "Greet with a sign" , "Hail respectfully" .)