Interesting finish you've got going on there, Steel Fan. I'm no machinist, but I've done a fair amount of bead blasting on old steel wheels for my car, as well as softer materials at a machine shop that I worked at. Given that glass is quite a bit harder than even hardened steel, I doubt the finish turned out uneven due to glass beads shattering. If that were the case, I don't know how Busse would ever get the DC finish in the first place. To me, it just looks like the uneven area was just not blasted quite enough. Either that or it was blasted with some really dirty medium that stained it (not sure if that's even possible). Like I said though, I'm not a machinist, so I may be wrong. Hopefully it all gets fixed somehow (either a complete DC finish or recoat).