I recently experimented with 150gr SST in my 270 to see if they were any better than the 135gr smk i have been using. The SST was a great disappointment. All 4 animals shot walked on before collapsing and meat damage was awful. The last one was the worst - shot at about 100m the bullet fragmented and the animal kept walking - it was shot behind the shoulder. I had to shoot it again before it expired. I have had brilliant results with the 135gr in 270 and intend to keep using them. A fellow hunter is looking into the jacket thickness difference between the 150gr SST and the 135gr smk - it looks at this stage if the smk is thicker but watch this space. When the results are out I will post again. Stick to the smk - you wont go wrong. The 168gr 308 bullet is legend!