Hey stgdz and OP,
The reason behind my first post was kind of a not so inside joke here on THR. When people start comparing the 550b (or XL650 for that matter) with the Hornady LNL AP, sh*t usually hits the fan. It makes for an interesting thread, to say the least.
I personally use the 550b for 223 but I do not use the Dillon as a full on progressive. I resize on my Lee Classic cast single stage and process my brass first, then I begin on the Dillon with seating the primer and then charging the case. I use a Dillon AT500 powder die with funnel and use my RCBS Charge master combo to throw Varget and charge this way. Then I seat projo, then crimp. I have found that it is still semi progressive but very hands on. I usually use Redding dies and I have a few different FL sizing dies (RCBS X die, Redding small base, Redding FL std, Dillon Carbide-which I still have not tried) and depending on the batch will determine what die I size with. Usually it's just the Redding FL std type A. I also use a Redding Comp seating die and Redding crimp die.
* * * From what I have seen of the Hornady LNL press, it's cool too.
Cheers