I am leaving the office at lunch today to go play. I have loads worked up for the 300WSM using H4350 and 155gr Sierra HPBT's. I bought the 155's for my 308 but after the box was open I realized I did not get the Palma's but they should provide a good baseline with the 300.
I hope the 300 shoots as good as my 270
Edit: I made it to the range about 1:00 this afternoon with the temperature somewhere between 95-98 degrees, wind was gusty from 10 o'clock. I froze my loads today and kept them on ice at the range and cooled the barrel between shots 2 and 3 and shot the Cooper 22 between three shot groups. These are the first six groups I have shot with this rifle.Target 1 - Sierra 155gr MK's over H4350, Group 1 and 2.
First group, shots one and two almost touching, I most definitely pulled shot three because I saw white between my vertical crosshair and the vertical bar on my target when the round fired. Second group shots one and two almost touching again and third to the right.
Target 2 - Sierra 155gr MK's over H4350, Group 3.
I moved the POI down 2" and fired the first shot off the paper and realized I moved the POI up 2", so I moved the POI back down 2" and shot the next two (shot one was up 1.5" and right .5" from these two).
Nosler 168gr J4 over H4350, Group 1.
Moved the POI down 2" and fired the next three, shots 1 and 2 touching but 2" horizontal.
Target 3 - Nosler 168gr J4 over H4350, Groups 2 and 3.
The J4's and H4350 did not group well in my opinion and truthfully, I have had better luck with Sierra MK's than J4's but I had a few leftover so I tried them. Next up will be some 168gr Ballistic Tips that I have on hand and fine tuning the 155gr MK loads that were a full .5gr apart.