Over the past 44 years I have been guiding I tried numerous rifles, calibers and bullets. Mostly because I am curious and also because after writing for hunting and shooting magazines I had companies wanting me to try, and tout, their products.
But ever since I started carrying the 458 the easiest ammo to get was the 500 gr Hornady soft nose and it has always worked perfectly . I used the newest steel jacketed DGX loads in Zimbabwe and they worked just as well on Cape buffalo as they do in our big bears; which are actually similar in size to buffalo.