AlphaMiner, The issue is indeed the model rail you ordered. The rail kit you have is in order to mount the cable management attachment shown below. [IMAGE] The rail kit you would need would be part number 53D7M. Which are blunt on the ends. [IMAGE]  Let me know if this helps. 
See photo, [IMAGE] I have a brand new PowerEdge R430 server that I'm trying to install into a server cabinet. When I built the server on Dell.com, I picked this option, "ReadyRails Sliding Rails With Cable Management Arm" I'm able to install the server in the server cabinet. But there's this piece of metal that sticks out in the back. I suppose this is the "cable management arm"? While this would not be a problem if I had an open post rack, but I have a server cabinet with a door in the back. This prevents me from closing the door! Even if I manage to take out this "cable management arm" by taking out those two screws, there's still some metal sticking out that prevents the door from closing completely. Any suggestions on what to do? Thanks in advance. 
PowerEdge R430 Mounting Rail Sticks Out -- Can't Close Server Cabinet Door