Okay, here it is, on rapidshare. Of course, as it is a FBI thing, it's about cops, handguns and criminals rather than soldiers, rifles and insurgents, but basically it works for both.
One-Shot Drops
Surviving the Myth
By ANTHONY J. PINIZZOTTO, Ph.D., HARRY A. KERN,
M.Ed., and EDWARD F. DAVIS, M.S.
Federal Bureau of Investigation Law Enforcement Bulletin - October 2004 Issue
http://rapidshare.com/files/139001293/Ersttreffer-Mythos.pdf.html
For those who don't wanna read the whole thing, one story out of it:
"In a final case, the subject shot the victim officer in the chest with a handgun and fled. The officer, wearing a bullet-resistant vest, returned gunfire. The officer’s partner observed the incident and also fired at the offender. Subsequent investigation determined that the individual was hit 13 times and, yet, ran several blocks to a gang member’s house. He later said, “I was so scared by all those shots; it sounded like the Fourth of July.” Again, according to the subject, his wounds “only started to hurt when I woke up in the hospital.” The officers had used 9-millimeter, department-issued ammunition. The surviving officers re ported that they felt vulnerable."
And to finally get back to topic: Wwith a 6,8 Grendel or even a 7,62 NATO you wont necessarily achieve better "drop-rates" than with a 5,56 round. The difference is not that huge.