Goes all out to make Grant’s epitaph? (4,3)

I believe the answer is:

lets rip

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'goes all out to' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.

'grant's epitaph?' is the wordplay.
'grant's' becomes 'let's'.
'epitaph?' becomes 'RIP' (rest in peace).
'lets'+'rip'='LETS RIP'

'make' acts as a link.

Can you help me to learn more?

(Other definitions for lets rip that I've seen before include "puts his foot down" , "Vigorously proceeds" .)

I've seen this clue in the Sydney Morning Herald.

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