I'm currently shooting the Nosler 55 gr. BTs out of my 22-250 using Win 760 powder and CCI 200 primers. Varget and H380 seem to be two of the more popular powders for 22-250. I personally don't think that choice of primer is that important, and I almost always use CCI just because that's usually what I have on hand and can find easy. Some guys might choose a magnum primer for ball powder loads, but I haven't had any issues using regular large rifle primers and Win 760. I like the ball powders because the meter very consistently.