As a follow up...
I did receive my expanders from NOE... in lightning fast time, too, even considering the lazy post office. The Lee Universal expander die is simple enough, but looking at the stock Lee expander inserts... it's unlikely I would ever use them, the angle of them seems too abrupt. I've not used them, however, but that was my impression just looking at them.
The original question I had was whether or not I needed to run the factory expander through the necks when resizing... and then using an additional, stepped expander in a separate step before seating cast bullets. The answer, at least with using the NOE inserts, is YES, I will have to run the standard expander through. Why? Because the NOE insert isn't long enough to expand the entire neck of the .348 brass... it leaves a little 'waist' right at the bottom of the neck, prior to the shoulder. If I seated a bullet this way, the constriction would likely swage the base of the bullet down, and could possible dislodge the gas check... at least, that's what I'm seeing. If the expander was just 1/4" longer, it would expand the entire length of the neck. Looking at Walkalong's Sinclair (et al) expanders... they look long enough to do so (judging only by the photo.) I could see where this might be a problem with other long neck brass, like .30-30, but not something like .308, both of which I load cast for.
Good news, bad news...
In the end, I did solve one of my problems... I actually got the correct expander for my bullet. I was actually using a .35 Remington M-die, because Lyman doesn't make one for the .348, so I will wind up working the necks slightly less. The other issue is case trimming... as someone mentioned, using the standard expander will allow me to get the trimmer pilot in so I can trim the brass without an additional step prior.
