Revolver we'll hear (5)
I believe the answer is:
wheel
'revolver' is the definition.
(wheels revolve around)
'we'll hear' is the wordplay.
'hear' indicates a 'sounds like' (homophone) clue.
'well' is a homophone of 'WHEEL'.
(Other definitions for wheel that I've seen before include "Catherine -; gear -" , "revolutionary device" , "Parade order" , "Rotating circular frame" , "Go round" .)