Grave scene of western battle (9)
I believe the answer is:
tombstone
'grave scene of western battle' is the definition.
'tombstone' can be an answer for 'grave' (thesaurus). I am not sure about the 'scene of western battle' bit.
'grave scene of western battle' is the wordplay.
'grave' becomes 'tomb' (synonyms).
'scene of western battle' becomes 'stone' (I can't explain this - if you can you should give a lot more credence to this answer).
'tomb'+'stone'='TOMBSTONE'
Can you help me to learn more?
(Other definitions for tombstone that I've seen before include "Memorial in churchyard - town in Arizona" , "Last monument" , "Does it display departure date" , "Graveyard marker" , "film location" .)