In this Matrix blade series, runners are not designed to be replaceable. Locking screws are glued and you need to heat them, if you want to open them without damaging the threads or screw head.
There was clear evidences that runner has hammered locking screws as well as the aluminum chassis. This is the reason why runner may get loosened where there comes clearance which is getting larger and larger when blades are used. Blade lifetime could probably extended a bit if Ultima would sell these locking screws and they would replaced from time to time. As you can see, it would not be mission impossible.
