I’ve been looking for the 357/38Spec and 9mm Shot Cups to roll my own. They must be selling all their production of cups as finished ammo.
I like Speer bullets, my favorite bullet for 5.56x45 is Speer 70gr semi spitzer. Old bullet that was very popular in 22-250 loads. Like it because it has a square base, minimizes the protrusion inside the case. Am very cautious about using heavy bullets that are long enough to reduce case volume at the same time you are trying to increase the charge. Hard to evaluate the pressure range. (5.56 is pretty forgiving on hot loads)
I get cups from Cabela’s.