Re: 300wsm h4350 05 h4831
All the above powders "seem" to work well in the 300WSM. Myself, I have had great results using the H4350 and the 208 A-max... though it's of the coarse grain and you spoke of using the finer grain powders.
Lately, with the powder supplies dwindling, I have been looking into other powders that seem more available in my area. This past weekend, I went out with some "testers" loaded up to see if any showed promise.
Results are as follows...
My usual groups are 1 1/2 inch @ 200 yds using the 208 A-max with 58.5 grn of H4350 and CCI mag primers. (yeah, I know... I suck) using a Tikka T3 Varmint SS with 23 3/4" Varmint contour barrel.
#1 Superformance. 208 A-max with 57 grn of Superformance and CCI mag primers. No signs of pressure... and grouping was 2 1/4 @ 200 yds. 5 shots
#2 Hodgdon H380. 208 A-max with 56.5 grn of H380 and CCi mag primers. Once again, no signs of pressure and grouping was 2 1/4 @ 200 yds. 5 shots
As you can see, there are many powders available... it's just a matter of finding the sweet spot that "your" firearm likes.
I also tried a heavier load with the H4350 at 59 grn... BIG signs of pressure and I only shot two before I boxed the rest.
NOTE: H380 and Superformance are of the small grain style. OAL was 2.900 and it was hotter than Hades here that day (31c).