I use 2 different sets of rcbs reloading dies, 1 for the 38spl & the other for the 357's. Bought them both decades ago used at gunshows.

I do use a lyman m-die with those rcbs dies. The rcbs expanders are designed for the smaller in diameter/shorter jacketed bullets. I use the rcbs expander with jacketed bullets and the lyman m-die with cast/coated/plated bullets.

RCBS makes different seating stems for different bullet nose shapes/designs. 1 set I bought had a small indent flat faced seating stem for wc/swc bullets. The other set had deep swc faced seating stem that also worked for wc/swc bullets. I called rcbs and they sent me (free) a rn seating stem.

Those rcbs dies have served me well over the decades producing quality ammo that has fed a bunch of different firearms.