Die set questions, Cast vs Jwords

So, after trolling through the back posts here,
I see I may need to do something about dies for my Argentine 7.65x53.
I've been shooting jwords but I have a mold on order from NOE for cast.
I understand there is some concern about popular dies for jacketed slugs, being to small,
and under sizing my carefully crafted little lead buddies during seating.
I've been using RCBS dies. I am going to have a problem here correct?
What flavor dies are recommended in order to not size my boolits while seating?
I am going to be getting a mold for the .308 as well, same thing applies.
Somebody set me straight!
Thanks

This has been my experience and may not reflect that of others:
I've found Lyman seating dies to be the most friendly for cast boolits, even if they are somewhat fat for caliber. And, I prefer their expander/M-die over the flare type dies. Additionally, they have interchangable seating stems that match most of the common nose profiles.

The thing is most die sets for rifles are two die sets, no expander. So whatever brand you buy, you will still need an expander/ neck flaring tool.

It really depends on how small your sizing die squeezes the neck of your brass. adn how much neck tension you want or need.

Granted the Lyman M die is one of the best ways to expand necks for cast boolit use, but I have loaded an awful lot of .308 and larger calibers by using the neck expander from a set of RCBS .30 Carbine dies. I put just a small flare at the neck, so the boolit doesn't shave while seating.

Robert

If your just shooting the 765 arg in the same gun with cast and your not shooting full power loads .
But say something with trail boss in it .I have found
that just barely neck sizing and depriming is all I have to do.Some like my 6.5x55 I just de prime re prime add powder and seat the bullet without even resizing. Using that lee tumble lube -my 2 cents

I have never had the problems with seating dies that some folks speak of on this board. Maybe I am just lucky. Were I in you shoes I would size in the regular size die. Expand with a Lyman M die and seat in your seater. I would no assume there is a problem until it pops up.

When I size, I always remove the expander ball and decaping stem. I knock out the spent primers with a Wilson punch and base. The set for the 30-06 takes care of most cases with that head size. A little slower, but the brass is worked less. That dragging expander ball contributes to case neck stretching.

I have the Lee universal case expander die so the flare is no issue.
I was concerned about the seater squishing the cast boolits.
I loaded 40 rounds this morning without issue, so maybe I got lucky :D
I only neck size the Argentine as well.

Maybe this is mainly a concern with handgun loads?