Re: 264 win. mag load data.
Mine shoots best with about 66.5 grains of h1000. Retumbo was good also, but h1000 gave better groups and lower ES for me. I would say to try each at 200 yards if possible. I would also start with the bullet just off the lands. If they don't work try different seating depths with each and don't forget to try different primers. WLRM primers seem to be consistently more accurate for me in the magnum cases that I load for.