I was just watching the episode w/ the new assault rifle....The Grendel, yes I found is interesting. The part that caught my attention was the kinetic energy test. 3 shots with the 5.56 and one shot with the 6.5, forget the AK for now. I'm an avid shooter myself so I could help but notice that the 3 shots with the 5.56 impacted the target below the center of mass, and the 6.5mm was a head shot. It looked to me that it's simple physics when it comes to knocking down a target. the lower the point of impact the less leverage is available to knock the target down, as was the case w/ the 5.56. As opposed to the single head shot that would provide plenty of leverage to knock a target. I think either way, if the round hits you, you are toast. But looking at it strictly for knock down power, looked like the cards were stacked in favor of the 6.5mm. Your thoughts.