There isn't enough difference in the terminal performance on game between the 9.3X62 and the .375 H&H that the .375 could be considered an upgrade; in fact given the time it takes to recover from the additional recoil, and the necessity of a physically larger, heavier rifle, it could be considered a disadvantage. So the choice then is to choose a high speed .375 like an Ultra or a .378, or go bigger, to which the .416 bores are the next natural progression. Frankly, I think I'd jump right to a .458 bore rifle, since the 9.3X62 covers the medium role pretty well, with bullet weights up to 325 grs. But if I was to purchase another .45 caliber rifle, it would not be a .458, neither a Winchester or a Lott. I would have the rifle chambered for either a .458 Ultra, or a .460 Weatherby. C-FBMI, IIRC, made up a few rounds of .458 Ruger, but I don't recall if he built a rifle to fire them in. My logic in all of this is less towards improved performance, although performance of the larger rounds are faster if you care to load them that way, but more importantly, a bottle neck cartridge cycles better than a straight wall cartridge in a bolt action rifle. Now I had an old Whitworth Mauser that fed .458s without a hiccup, but my M-70 has an issue in that the rim of the extracted cartridge catches the case mouth of the top round in the magazine, sometimes stopping the rearward progression of the bolt and making a burr on the case mouth. Crimping only solves the problem if the bullet has a deep crimping groove, like a TSX, an A-Frame, or a cast bullet, but if your jacketed bullet has a knurled cannelure, it doesn't allow the case mouth to form tightly enough to the bullet to avoid catching the rim of an extracted round. If the cartridge is bottle necked, at worse the rim of the extracted cartridge will touch the shoulder of the top round in the magazine, and will cause no functioning problems. The downside of a bottle neck cartridge is that you will need a drop box magazine to maintain the same number of rounds as a .458 will hold.