Blade on a rifle (7)
I believe the answer is:
bayonet
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">blade on a rifle</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 bayonet that I've seen before include "one's attached to one's rifle - that's sort of fitting" , "Pointed weapon" , "Knife fixed to the end of a rifle" , "Neat boy (anag.)" , "Muzzle blade" .)