Opening drink, knocked back shooters (7)

I believe the answer is:
pistols
'shooters' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Perhaps you can see a link between them that I can't see?
'opening drink knocked back' is the wordplay.
'opening' becomes 'slot' (slot is a kind of opening).
'drink' becomes 'sip' (sipping is a kind of drinking).
'knocked back' shows that the letters should be reversed in order.
'slot'+'sip'='slotsip'
'slotsip' written backwards gives 'PISTOLS'.
Can you help me to learn more?
(Other definitions for pistols that I've seen before include "weapons" , "Handguns" , "Guns" .)
