RE: new 22-250
22-250 is pretty forgiving to the handloader. I'm at school and don't have my books with me...but Varget is very popular, H-380 (hodgdons) was named because the develper/owner's pet load was 38.0gr of H-380 for the 22-250. There are probably a dozen or more powders out there that could be agreed upon as EXCELLENT powders to use in the 22-250. As far as bullets I'd find the cheapest thing that's accurate for crow and paper. Regardless of what that bullet does when it hits the 22-250 could kill a crow 10 times over. No need for magnum primers, but I suppose if you find a recipe using them then give 'em a try.
There's A LOT of websites out there about loading the 22-250...type something in google and your bound to have all sorts of recipes, just be very careful with online unpublished data.