Recoil is calculated like muzzle energy, but felt recoil is highly affected by bullet weight. In other words, if you loaded you 458 to the same muzzle energy with a 350 and a 500, the 500 will kick harder. That's because the extra inertia of the 500 is pushing harder on the rifle. Extra weight in the rifle will help a little, but it's the bullet weight that makes the biggest difference. That said, it's also the bullet weight that makes the biggest difference on the other end - so size you bullet for the task. I have a 375 H&H and will work up a load for 235, 270, 300, and 350 - but will mostly shoot the 235. If I ever go on safari I'll take the 300 and 350. The problem with the 416 is it only comes with a 400, and unless you slow it down to 2000 fps, it will hurt every shot. Therefor, your 458 or a 470 nitro with full loads and a 500 will pound you. This was a very difficult desion for me, because I know the 375 is not the best cartridge for a double, but I am sensitive to recoil and could not take the 470 or 416 very much.