Member of sporting party possibly one trained on the range? (3)
I believe the answer is:
gun
This clue is a double definition.
'member of sporting party possibly' is the first definition.
(gun can mean someone on a shooting trip)
'one trained on the range?' is the second definition.
(as in training on a shooting range)
(Other definitions for gun that I've seen before include "What has barrel" , "Throttle" , "Revolver" , "Rev up" , "Shooter" .)