Well, thanks for the input. There is no doubt I am using the correct end of the stem, as I said the other end works well for swc's. It sounds like others have the same problem also, so I'll just stick with the RCBS seating die, although I do like the design of the Dillon for cleaning purposes.
As far as contacting Dillon, I was twice told this is normal, and no offer of replacement. All a replacement would do is to give me another paperweight because I believe the problem to be in the design. The way it is made, the edge of the stem is .52 wide and squared, instead of coming out to meet the die inside wall which would eliminate the contact point.
I only use Hornady 230 lead rn and Berry's 230 gn plated so the shape shouldn't be a problem. Could it be possible that they included a stem for a lesser caliber? Looks like a .40 would fit in there just right.