It’s always interesting that when someone mentions using a Lee FCD, somebody says that the use hides an underlying problem with the reloading. It’s usually something “they heard”. I never run 38 rounds through it, but always run 357 hard cast lead rounds through it. Most of the 357 rounds just pass in and out, but I can feel the occasional round touch the die lightly. I hardly ever need the FCD for JHP rounds. That tells me that what the die is actually doing (for the most part) is making the hard cast lead bullets dimensionally the same.
On the rare occasion, a JHP round will need to go through the FCD, and that takes care of the slight bulge in the case. Now...how and why would a case ever get a bulge if the bullets and cases are all exactly the same? The die is set the same way. Nothing is different. Well, it is my firm belief that a 357 case might be just a hair longer than the rest, and when the longer case is crimped, you get that bulge. Does that sound like improper load technique?
So, buy an FCD or don’t. I don’t care. I’ll keep mine.