Serviceman, possibly, using a rifle (5)
I believe the answer is:
flier
'serviceman' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'using a rifle' is the wordplay.
'using' indicates anagramming the letters (the letters used in a different way).
'rifle' with letters rearranged gives 'FLIER'.
'possibly' is the link.
Can you help me to learn more?
(Other definitions for flier that I've seen before include "Rifle for airman" , "Circular" , "Leaflet for distribution" , "Risk" , "Aviator" .)