Energy versus velocity? Maybe some people have no grasp of physics or terminology?

Kinetic energy= 1/2 mass x (velocity x velocity)

Actually, neither speed or energy kills, accuracy does. You can't miss them hard enough or fast enough to kill 'em.

I agree that certain bullets are better for certain jobs, but I think people concentrate way too hard on picking that perfect bullet. My great grandfather, grandfather, uncles, cousins, and I have been using regular old soft point lead core bullets for years and years, and have never had any problems killing elk or moose. My dad shoots a 30-06 with 150gr Remington core-lokt bullets as he has for years, and several of my uncles shoot 270's with 140gr core-lokt bullets as they have for years. I now use 150gr Sierra Gameking bullets in my 7mm mag. None of us has ever had any problems killing elk, and we can break their shoulders just as easily as anyone else out there. I shot 160gr Nosler Partitions one season, and cannot tell any difference between them and the 150gr boat tails I'm shooting now other than the fact that my 150's shoot faster and flatter. Unless you're shooting light, explode on impact nosler ballistic tips or heavy bullets that barely expand like failsafes, I don't think you're going to notice much of a difference in performance.

For deer, I use the Nosler Ballistic tips in almost every caliber. My next favorite is the Sierre Pro Hunter. The Partition is what I load when both deer and bigger game is possible. The Ballistic tips have been changed at least five times since they came out. Now the lighter bullet per caliber are for Varmits and the heavier per caliber are for big game. I had a few problem with the real early ones in the 7 Mag but since then, not a single case of lesss than perfect performamce.

I have used almost every factory loaded bullet made and have never really had any problems with any of them. I won't use Gamekings and I won't use Speer Hotcore unless the are recuced loads.

There is a problem using section density as the key to how a bullet will penetrate. It is a clue, but not the key. First you have to look at the formula: Sectional Density = (Wt. in Grains/7,000) / (Dia.* Dia.). As you can see bullet construction is nowhere in the formula. It is only a relationship of weight to bullet diameter. This means you could have a bonded premium-hunting bullet with the same SD as a ballistic tip varmint bullet. Thus bullet construction actually has more bearing on actual performance in the field.

Thats exactly why I said that its part of the formula. You must have a certain amount of SD to construct a bullet that will penetrate. As far as useing it to select a bullet, most factory loads make no mention of the SD of the bullet used.