I'm rebuilding the drop targets on my Blackout and discovered I have the same problem - cracked bosses on the guides. I came up with an easy fix. I checked my old modeling supply and found some brass tubing (7/32" - I think). It fit snugly over the bosses. I cut a few pieces just under 1/4" and slipped them over the bosses. Seems to work fine - the screws hold tight now.