Yes, I have the same concepts about belling, crimping, champering. I experienced shaving of the base of the plated bullet in my original setup, then belled more to allow the base to start easily; then I experienced the bullet being seating off the line of the bore, ie the bottom was on line, but the top veered to the right some,.........so when rolled on the table, the nose would go up/down...........kinda embarrassing to an old guy.
So with that, I belled more and thought I was there; but still have say 10% that will not gage.
a belling rod has the belling feature, but also has a lower feature to normalize the resized case where the bullet ends up. I am using mixed brass, like the other 30 years without troubles, but do notice differences in pressure to seat a plated bullet; even maxibelling.
I may examine the belling feature as to both bell and expanding features to see if that makes sense. I can always make one up I reckon but not sure if I am up the right tree yet or not. My reloading dies for the 9mm are not Dillon,and are economy type one might say, but been ok so far. I have scrapped 30 Luger dies by this vendor, but the 9mm straight wall has always been ok; well for a long time anyway. Perhaps time to use my head rather than just trust what I can buy.
It may be possible, that the plated bullet does not glide down gracefully down the belled(internally sized) case too good. Guess been at it too long, might have to take a breather to see the measuring sticks right again.
Might as well do a looking at the seater too............or heck, go buy a set of expensive dies huh?.............
..........maybe whine to a couple of friends to borrow a high quality die set.
thanks for the pointers and good wishes..............