It's a revolver, this weapon (9)
I believe the answer is:
boomerang
'this weapon' is the definition.
(boomerang is a kind of weapon)
'it's a revolver' is the wordplay.
I cannot quite understand how this works, but
'a' could be 'an' and 'an' is located in the answer.
'it' could be 'e' ('e' can mean 'electronic' which is similar to 'IT') and 'e' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for boomerang that I've seen before include ""It keeps coming back"" , "Aboriginal weapon" , "Backfire" , "Curved throwing stick" , "Recoil from" .)