I live in bear country.
I have found after many bears that a 30-06 with a 200 grain Accubond kills equally with any of the mediums which I have had many.
Velocity is 2650-2700 ft/s depending on powder.
Defense action on bears are super short range proposition , when hunting bear the ranges are generally short almost never more than 150 yards.
Bears are not that hard to kill, but they do not stop easily unless a through the shoulder shot is used.
Hence the 150 yard general limit.