I have used 120 NBT's with a 14" 260 Rem up to elk with no problems, and have used the 7mm 120 NBT's up to mule deer-great results, and have used the 140 grain 7mm NBT in the 7-08 and the 284 Win up to elk-Awesome. Even used the 30 cal 150 NBT @ 3000 fps MV in a 7.82 Patriot XP. Dropped a large cow elk like a hammer with exit @ 300 yards. Used the same bullet to take whitetails as well.
I don't use NBT's much anymore, but it is not because of their effectiveness, but rather has more to do with drop and drift.