It's my understanding that when Nosler tested the 150AB vs the NBT, the AB produced no performance advantage over the NBT. The 150gr NBT is tougher than you might think.
I'm not so sure about the toughness of the 150 grain Ballistic Tips. I shot an antelope at a little over 300 yards with my 270 Win. The shot was broadside, hit him behind the shoulder, the bullet nicked a rib going in and destroyed the lungs but didn't touch the far side of the body cavity. That's not very tough in my opinion. I would have thought it would have penetrated completely in that scenario.
How long ago was that? I only ask because Nosler has beefed up the jackets on many, if not all, ballistic tip hunting bullet over the years. They were pretty fragile for years to the extent that was their reputation. I don't know the timeline for when they did this. I do recall Mule Deer touching on this numerous times in his articles.
For what it's worth, I would have guessed the reason it doesn't exist is that the 150 BT is tough enough for typical impact velocities of the majority of 270 cartridges.
