One who keeps saying 'Winchester'? (8)

I believe the answer is:

repeater

I'm a little stuck... Click here to teach me more about this clue!

But I can't explain it at all! Could you help me understand?

(Other definitions for repeater that I've seen before include "Handgun able to fire again without reloading" , "Amplifier in phone line" , "A salesman" , "it's dangerous" , "Timepiece striking the hours" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app