Beater's replacement misusing air rifle hit a cat (10,5)

I believe the answer is:

artificial heart

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'beater's replacement' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.

'misusing air rifle hit a cat' is the wordplay.
'misusing' indicates an anagram.
'air'+'rifle'+'hit'+'a'+'cat'='airriflehitacat'
'airriflehitacat' with letters rearranged gives 'ARTIFICIAL HEART'.

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I've seen this clue in The Times.

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