Agreed.
I tend to follow the 1,000 foot pound for Deer, Pig, and black bear at the distance the animal is from me, as a rule
and the 2,000 for larger animals (elk, moose, brown bear).
Now will I shoot a deer with 750 foot pounds and a heavy for caliber bullet at distance- Yep!
This same rule is what makes the 30 Carbine marginal for Deer. It will not break the 1,000 Foot pounds mark. But it and the 22 Hornet will Kill deer if hit right. The little Hornet start out with 723 foot pounds for a 45 grain bullet. At 100 yards it drops to 417 but I have seen swamp deer in NC drop in their tracks to a 22 Hornet with a chest hit. like hit with lightning dead!
Getting back to the 30-30
The 150 grain 30-30 will carries that magic 1,000 foot pounds to 200 yards (858 to 989 Foot pounds) At 500 yards it is still has 425 foot pounds of energy and that is about what a 45 ACP/ 45 Colt has with a 230 grain bullet at the muzzle or what the 22 hornet has with a bullet 3X the weight and 1.375 X the diameter.
Even the 44 Mag only carries 699 with a 270 grain bullet to the 100 yard mark.
The 180 and 240's are only in the mid 500's (551 & 543 to be exact)
even right out of the tube they are
180= 1036 foot pounds
240= 741
and the big boy 275 is 931. And everyone says a 44 revolver is fine for game as big as elk, moose, and brown bear.
The 30-30 starts with almost 2,000 foot pounds or twice the energy of a 44mag.
The 454 Casull will carry 1,187 foot pounds with a 300 grain bullet out to 100 yards.
Now with my 6.5X55 it will easily carry the 1,000 foot pounds with the 140 grain bullet to the 500 Yard mark so at .3 of a mile my 6.5X55 sweed is still a deer gun.
The 165 grain bullets I shoot out of my 308 (while I max my shots to 350 with my M700V on game) will still carry up to 1200 foot pounds out to 500 yards. and at 1" groups at 100 yards on a bad day that expands out to 5 to 6 inch groups at 500 yards still with in the kill zone of a deer aiming for a lung shot.
All of my numbers came off of the Remington Website. (except the 6.5X55 I used the 260 Rem as they are the same ballistics different case) And all 30-30 info is with round nose bullets. Pointed bullets will carry more speed at given distances increasing the Foot pounds for that distance.