The 150s are fine to about 800 yards. After that you would need rediculously high pressures to remain hypersonic. If you want to make it to 1000 yards at hypersonic speeds then you need to look at bullets of 155 grains or heavier.
Having said that, you can squeeze a little more distance out of it if your barrel twist rate is faster. The whole idea is that bullet stability is dependent upon both spin rate and velocity. With lower velocity you need more spin to maintain acceptable stability. So if we accept that as true, it would be reasoanble to conclude that a rifle with a 1 in 10 twist would shoot accurately a little further than a rifle with a 1 in 13 twist.
Now that's not to say that we should all run out and buy some super fast twist barrel. There is a cost to spinning bullets faster and that is a reduction in accuracy. Basically an analogy might be that if you drive slowly with a tire that is out of balance you dont notice it, but as you drive faster the wheel starts to vibrate. The same goes for bullets, Spin them faster and the bullets need to be perfectly balanced or they bounce all over the place.
If you buy really great bullets, you may never notice problems.
The general rule is that best accuracy is achieved when you have just barely enough spin to stabalize the bullet, anything extra is your saftey margin for cold days and low temperatures.
Berger Bullets has a bullet stability calculator on thier web site that you might want to check out.
