^thisThe bullet needs adequate velocity to perform as designed.
Guns range needs to be determined for hunting by where the bullet performs and loading will dictate that speed.
A corelokt 300 win mag factory load for instance Peter's out at 400 yard. But put a proper pill and you can extend that range.
Each person needs to really decide what there conscience, skill, and equipment is going to do. I dont go by "energy" to determine that. States use that to try and keep the equipment up to snuff for big game. Others have caliber size limit ect...those are guidlines and minimums.