Chums making hit, going up (4)

I believe the answer is:

pals

'chums' is the definition.
(I know this)

'hit going up' is the wordplay.
'hit' becomes 'slap' (both can mean to strike).
'going up' shows that the letters should be reversed in order (in a down clue, the letters are written upwards).
'slap' in reverse letter order is 'PALS'.

'making' acts as a link.

(Another definition for pals that I've seen is " Friends".)

I've seen this clue in The Guardian.

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