I checked it tonite, and I now see a huge crack near the seam, but not involving the seam. And that makes the drum weak, and it flexes in that area, so at the bottom of its travel the weight of the laundry is obviously flexing it downward and that screw head is scraping on something. So I'm off to order a new drum! Oh, and the screws only hold the internal grey 'fins', the drum in that spot is actually quite thin.
In the morning I'll post a few pics, just in case it might help someone else to know what to look for.