What secures arm in place for drawing? (7)

I believe the answer is:

holster

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'place for drawing?' is the definition.
(I've seen this in another clue)

I cannot understand how the rest of the clue works.

(Other definitions for holster that I've seen before include "Pistol case" , "put gun away" , "Pistol sheath" , "armrest" , "Pistol-holder" .)

I've seen this clue in The Telegraph and The Sun.

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