This is pretty basic stuff here guys. The 30-06 is limited to 60,000 PSI by SAAMI, while the Ackley is not. That's where you are seeing a significant portion of the gain.
Do the math on the case capacity difference (4 to 1 rule), and you come up with around 20-25 fps difference at equal pressure. In other words, an inch of barrel length.
Do the math on the capacity of 7mm Rem Mag vs 7mm Wea. You should get about the same 25 fps velocity difference. In the real world, it just ain't so.
If it was just about case volume and maximum pressure, the Nosler load manual would list a higher max velocity for the 165 than for the 180.
Powder choice and pressure curve duration also matter.
