When I had my Winchester M/70 rebored to .35 Whelen several years ago I did extensive load development and range testing. 225gr. Sierra and Nosler bullets shot the most accurately in my rifle, powder of choice is IMR 4064. I have taken an 8pt. whitetail buck with the 225gr. Sierra, the bullet performed well. Hope you find this info useful in developing a load for your .358.
