Gun dogs? (3-3)

I believe the answer is:

pom-pom

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'gun' is the definition.
(I know that pom-pom is a type of gun)

I cannot understand how the rest of the clue works.

(Other definitions for pom-pom that I've seen before include "Decorative tuft or ball - mop up twice" , "Fluffy decorative ball" , "Form of dahlia" , "Fluffy ball - type of gun" , "Ball of tufted wool, on a hat perhaps" .)

I've seen this clue in the Evening Standard.

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