Von S. says, "For me I am truly a firm believer that the 458 win mag should be the absolute minimum to shoot all of the "Big 5"." To each his own, but that is rather extreme. You should perhaps add to that, for those that can handle the recoil. Absolute minimum? So maybe a 505 Gibbs for leo would be good? You must have read a lot of Elmer Keith! He once wrote that the .270 Win was a damned adequate coyote rifle! Many have taken the Big 5 with much less than the .458 and lived to tell the tale. You mention "cape" a couple of times. Cape buffalo? They are tough, I have taken two, both with a .375. First one was not hit well, and the PH and I shot again, both .375's btw and dropped it. My second buff was taken at over 140 yards, moving, with the same .375 and dropped stone dead to one shot. I think the .375 is damned adequate for buffalo when properly hit. JMHO.