RE: Anyone believe in high-velocity killing power?
There is only one thing that will cause instant death and that is a shot to the brain. Period end of story. Regardless of how fast or slow a bullet is traveling at impact.
No a spine shot does not cause instant death. It causes instant paralysis until the brain is depleated of oxygen and dies.
A faster bullet with adequate construction can cause the animal to drop right then but it still isn't dead. The theory is that the faster bullet causes more shock to the body and with perfect timing can cause instant ruptures of blood vessels in the brain basically causing a massive stroke and causing the animal to collapse.