Revolver found at entrance to ground? (9)
I believe the answer is:
turnstile
'revolver found at entrance to ground' is the definition.
(revolving device at a sports ground)
This is the entire clue.
(Other definitions for turnstile that I've seen before include "What controls access" , "where spectators pass" , "Means of regulating passage" , "Control for spectators' entry" , "Crowd-controlling gate, at entrance to sports-ground say" .)