It's not energy, it's the damage the bullet can do that matters. A hunting max range would need a standard for testing. First determine a minimum penetration requirement for the size of game. Max hunting range would be where the bullet still upset and met the penetration minimum.
Roger that. Algebra is fun...you can create all kinds of neat formulas that give different numerical results to play with...but if it's about killing stuff, it comes down to physics and the shear destruction a given bullet will cause in the animal of your choice. The empirical data will come this season as those take this caliber to the field and do just that...kill stuff...then talk about what their bullets did and how/why they did it.
Unless AAC is going to resurrect the Strasbourg Test format and marry that with the FBI's ballistic testing program and load up some goats in an old car behind windshield glass wearing cute denim "shoot me" vests it's probably a moot discussion...although this would be a good marketing scheme for the next AAC Silencer Shoot in my opinion...