"Here's a little more detail:

95% of my hunting will be from the hill country west here in Texas. Shots range from >100 yards to over 600. Most of this hunting is from box blinds or taking a seat on the ground. The primary goal of this rifle is a solid 300 yd (or better with practice) rifle that will hold it's umph out to those ranges.
Game will primarily be whitetail and axis with a possibility of an Addax.
Out of state hunting will SE NM for mule deer and Idaho/Wyoming for elk and mule deer. Thinking of either the 220 grain or the 225 grain Sierra's or Nosler partitions"

SO OP - do you plan to take shots to 600 - with the 358?

Steve, how much incremental fps do you see per inch, and how does that impact trajectory?

If set on a 358, the 225 Sierra is the only bullet I would run in a 358, a Partition is a great choice and if close shots on Elk or Big Bears is a good one, esp in a 350 RM or Whelen or anything faster.

I had a M77 350 in SS, shot those two bullets great, the Sierra will expand and retain, and penetrate very well. Built for a purpose, big game.

My buddy had to buy it after hammering a nice 10pt WT, but if I did again, I would buy the same rifle, and chop to 20 or 21. That is the max I want in a short action 35. A 19 would not be out of the question. I would expect 15-20fps max per inch from 19 > 22, and to me, that would not mean squat downrange in performance.