Run into some of the defence (7)
I believe the answer is:
rampart
'the defence' is the definition.
(rampart is a kind of defence)
'run into some' is the wordplay.
'run into' becomes 'ram' (I've seen this in another clue).
'some' becomes 'part' (only part of something).
'ram'+'part'='RAMPART'
'of' is the link.
(Other definitions for rampart that I've seen before include "Broad defensive wall" , "section of defence?" , "Battlement, fortification" , "Military protection" , "barricade" .)