Re: 6.5 STW Loads
I am a long time 6.5 sufferer. I have just bought a pound of Vhitavuori N-570 and tried it in my 6.5 WSM with 140 Berger Hybrids and 160 Sierra SMPs. I can get about half a grain more of it than Retumbo in the case and correstponding 20 fps gain. It is a coarse stick powder. Each kernel weighs 0.03 grains. It is not as coarse as 50 BMG. N-570 burns as clean as Retumbo. Use magnum primers. 210Ms increased the ES and SD.
I have often wondered about VV 24N41. See Mark Pinkstons work with the .264 Thorr.
I never did get any velocity out of H-870 in the .264 Win Mag. This was a surplus powder and what I had was a disappointment. You could compress as much as you wanted to into a .264 case and it showed no signs of pressure or velocity. I even tried 1.5 grains of Red Dot over the primer to try to light a fire under it.