too much attention is payed to the physics of ballistics and not enough attention is payed to putting the bullet where it needs to go. there isn't a caliber out there that will take an elk of it's feet, unless it's a spine shot. they're fairly tough, good sized, and have huge lung and capillary capacity. it takes em a minute or 2, to expire. velocity, "knock down", bullet weight, bullet diameter, bullet type, penetration, etc., none of it means anything if you don't hit em right. a lung shot might take a minute or 2 for em to go down, but they are dead, no matter what. even if the bullet doesn't expand. lungs are real delicate tissue. you can rip them to shreds with your fingers. put a bullet from any modern day, center fire, hipower through an elks lungs, even a solid, and it will die and die pretty quick. something that is travelling at the speed a bullet does and is hard as a bullet is, is going to cause a devastating wound. sometimes, some elk, just run a little farther. as long as you retrieved it, ya did ok. this past Az. early bull hunt i saw some horrible shooting from some big guns. practice is what it takes.