I tried the 129 grain Hornady SST out of my 264 STW this morning and was very impressed with the accuracy of this bullet. I shot two groups of 1.4"-1.9" at 400 yards with these bullets. The Hornady published BC is way low on these as Bryan Litz also noted when he tested them. They all weighed out very close when loading them without having to seperate into groups. 83 grains of retumbo was the best load shooting a 1.4" group at the 400 yard target at 3661, 3672 and 3659 fps. 80 grains of magpro shot a 1.9" group at 400 yards at 3648, 3653 and 3661 fps. I love to get this rifle out and play with it every once in a while. It is a super shooter and incredible deer/antelope special. The rifle is a sako action with a 28" 1-8.5 twist and Mcmillan stock.