I like to neck brass up not down I will use the brass that is closes to the caliber I am necking to. Therefore I use 325 WSM brass. I use RL-17 and the 225 Mosler BT because it gives me the loading density I like, the speed I like and the accuracey I prefer. And it is my understanding that Winchester is using rl-17 for the 325 wsm loading.
