zzzzero,
I did some more checking for you since you now have added more information to the puzzle. Yes my 375 Win and 45-70 do come out of the Redding dies looking almost bottleneck. It is almost scary when you see them because you think they are over sized (compared to RCBS dies).
However, this gives a very tight fit on the bullet, not a loose fit as you described. I took the plug out of my Redding 45-70 sizer die. At first I thought there was a ring as you described, but upon further examination I found that it is just a reflection where the case stops in the die. There is no ring like a crimp die. I would say something is wrong with your die set and from my experience with Redding in the past they will take care of it quickly when they get back.
Sorry if I gave you bad info before, but the cases do come out of the dies with the end really sized small and I thought that was what you were talking about.
Good Luck.