There is no best one to start with ! Every gun is different and ussually likes a different powder. Don't kill the messenger ! Sometimes you get lucky and hit the nail on the head, first powder works perfectly. Other times it might be the 5th or 6th powder that is crazy accurate ! I would try us869 powder up around the 80 grains area. I like it in the 338 Lapua .I am looking to load for my new 7mm Rem Mag. I am planning on shooting a Berger 180 VLD Hunting. Don't want to waste a lot of time testing several different powders if I can get down to the best one to start with.
Thanks for any input