primer makes little difference in an stw as long as it's a mag primer. That said, a win lrm or fed 215 will have less soot than a cci 250. That is enough for me to go with one of the two in my rifle... I use 215's in my rifle in 7mm stw.
I loaded the 180 grain Hunting VLD with Retumbo and Fed 215 two years ago for hunting season. Was less than impressed with bullet performance on two animals. Accuracy was very good but on game performance they couldn't stand up to high speed anywhere up close.