I shoot 140 grain SST's out of a 270 WSM at 3150 fps.
They're very accurate in my rifle.
Dan
Good to hear about a positive experience even at higher velocities. The 140 is one that got a makeover as the originals were bombs. I think Hornaday beefed them up the second year of production.
Prose: Not too much experience with loading them but I treat them like any other pointy boat tail bullet and go from magazine length to way off the lands with 0.05 to 0.5" sometimes being the sweet spot. I think in general the accuracy potential is there just a matter of finding it.