Which powder should be the best to start with in 26" barrel 7mm Rem Mag with 140 gr. Nosler Accubonds out of these that I have on hand- H4350, H4831SC, H1000, Retumbo. Primarily for whitetail hunting out to 500-600 yards. By best I mean tightest and most consistent groups with top velocity. I also have some Fed215 and WLRM primers to use. Thanks in advance for your replies.