In my research and searching the rpf I have been looking for a dedicated thread to the mystery disc on the DL 44 Hero ANH. I could not find much, so I am starting a thread. If I have missed a thread than please forgive me. If this info is already know then sorry again. When I look at the Dl 44 mystery disc, I wonder and think, is it intentional? Why, was it a mistake? Well looking at the naked runner photo http://www.tested.com/art/makers/452186-how-obsessive-fans-built-better-han-solo-blaster/ It is clear that where the mystery disc is, there was a hole drilled into the mauser to mount the scope on that side. This rig was changed over to be mounted on the other side for ANH. This leaves a hole. I also wonder if maybe under the rail that the scope bracket slides onto may have had a washer. If this area was bare metal, or sanded to remove the bur from the hole, and then was painted while assembled, then on disassembly we may see a circular patch of bare metal and a central hole. Explaining the disk. So that is one posibility, the other may be that there was just the hole, (which would be easy enough to fill and paint black.) And then they used that hole with a forstner type bit and milled a circle removing the painted surface, and leaving what looks like a bare metal disk. So that's my opinion, I welcome others to debate and inform all us noobs who are researching to build our DL 44's.