I gave up on SST's. I've gotten irratic terminal performance.

I blew up a cape on a Speed Goat at 385 yds, 140 gr. SST out of my 6.5-284.

Of the two bullets you listed, the NBT's would be my pick.

But don't limit yourself to those two, try others. See what your gun performs best with. You'll never know until you try.

DF