Report turning warm…warmer! (7)
I believe the answer is:
gunshot
'report turning warm warmer' is the definition.
'gunshot' can be an answer for 'report' (I've seen this before). I'm unsure of the 'turning warm warmer' bit.
'report turning warm' is the wordplay.
'report turning' becomes 'guns' (I can't explain this - if you can you should give a lot more credence to this answer).
'warm' becomes 'hot' (associated in meaning).
'guns'+'hot'='GUNSHOT'
Can you help me to learn more?
(Other definitions for gunshot that I've seen before include "One fired" , "Range of a specific weapon" , "Crack" , "Noughts (anag)" , "Firing of hand weapon" .)