ROFLMAO! That statement is as humorous as reading Jeff Cooper on 9mm. And about as full of it.

7.62x39mm is equivalent to .30-30 in terms of effective range, general accuracy and kinetic energy. Where it is superior to the .30-30 is the ability to use spitzer tip bullets. .30-30 has taken as much game if not more than the .30-06, ranging from deer to hog to bear to moose. If you doubt it, there is a moose head in my parent's living room, and I know for a fact it was killed with a .30-30.

The only advantages that a larger .30 caliber round would give you, honestly, are improved accuracy, penetration of hard material and long range performance due to higher initial velocity. 3MOA works well enough for most things under 200m. In most situations, you aren't going to be shooting at game over 200m. And you aren't going to be trying to stop engine blocks or a water buffalo. But until you get out a ways, that higher speed isn't going to add anything in North America than polar or large brown bear. In CONUS, baring zoo escape, there's nothing in that class.