Smooth-bore weapon (7)
I believe the answer is:
shotgun
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">smooth-bore weapon</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for shotgun that I've seen before include "arm" , "No thugs (anag) - weapon" , "Firearm used at short range - kind of wedding" , "Noughts (anag) - type of wedding" , "Type of wedding - weapon" .)