Mystro, I have dropped them in their tracks with my 7 Rem mag ( 2 bucks weighing in at or over 300lbs on the hoof, 1 average sized buck & doe, Calf moose) Of the ones that mustered any distance they were found in less than 50 yards and were mostly a direct result of the shot(placement/distance). So while you and your pal haven't witnessed it, I can tell you a 7 rem mag can drop them flat. I certainly can tell you I have seen them drop from a lot of calibers and run seemily dead on their feet from a lot of calibers as well. Not saying your 300 winnies isn't packed full of wump but the comment of .30 over .284 don't float with me in regards to dropping an animal in its tracks, many other factors to consider.