I just ordered some 338 RUM dies from Redding with the micrometer to load my 250 grain Berger VLDs. Unfortunately, I am having the same problem you listed a few years ago. I saw that your fix was to throw the die on a lathe, and take .10 off of the seating plug and the micrometer. I wanted to know if this solved the problem for you?
Also, I don't have a lathe to cut the threads back on the plug and micrometer. Wondering what type of lathe you used, and if most machinists would be able to help me out?
Thx!