Like I posted start out with what seating depth fits in magazine well.(Its possible that could be to long,if so seat it to what book list) Slow burning powders are a must ,I wouldn't use anything faster then H4350 or Re#17.
I went with CCI LRM primers, IMR 4350, 130gr Accubonds, COL to factory length of the Winchester Ballistic Tip loads. I use Norma brass and Redding dies. The Winchester model 70 Super grade requires a partial full length resize for consistent feeding. These loads are 1/2 MOA at 100 yards. I am towards the top of Nosler load data for IMR 4350 and match the factory speeds of the Winchester Ballistic Tips. R19 was peaky, and R22 never got up to speed.
I have been loading 130 accubonds in winchester brass with 65.5 grains of reloader 19. This load shoots at 3158 with an extreme spread of 7 fps. I have not done a lot of LR hunting, but i plugged a coyote with this load a week ago at 721yds. This isnt the fastest load in the books but has been very accurate in all three of the 270 wsm's I owne.
It actually did better thana I thought! I was shoot ing from the top of a hill and the coyote was down in a draw across a pasture. It hit the coyote low in the chest and exited about the size of a qaurter about two inches above the tail he was sitting facing towards me. I have to say I was addicted to LR hunting after that! Watching the bullet hit after the crosshairs have sttled from the recoil was awsome!
I settled on Win brass, Fed215 primers, and IMR4350 with 62.5 grains using 140 Accubonds and Ballisic Tips. Groups with both in the .25-.5 MOA range with my Wnchester Supergrade Velocities run around 3200FPS with tight spreads. I have had issues with temp sensitivity with the Reloader powders.