Missile to stun borders of Egypt (6)
I believe the answer is:
rocket
'missile' is the definition.
(I've seen this in another clue)
'stun borders of egypt' is the wordplay.
'stun' becomes 'rock' (both can mean to shock).
'borders of' suggests removing the centre.
'egypt' with its centre removed is 'et'.
'rock'+'et'='ROCKET'
'to' is the link.
(Other definitions for rocket that I've seen before include "It is used to propel a spacecraft or missile" , "Salad leaves - move at great speed" , "Severe reprimand" , "Edible plant; weapon" , "Projectile lettuce" .)