I'd still pick the 375 Ruger just because it's shorter and will fit in magazines easier with the big bullets. It's not quite a 375 H&H Imp for speed but it still adds 100-150fps over the H&H and the brass is almost always available. I've owned a 375 RUM and it didn't get much more for speed than my 375-358STA plus the brass is getting hard to come by. I use to hunt elk with 250 Sierra's and 270 fails safes at 3080fps and just over 3000fps. The 375 H&H's I've owned were quite lethargic in comparison. R-15 would shoot 260's about 2800fps but that is the only powder that would do it. The problem with 2.850" length cases is you always fight the magazine length and the heavier bullets require deep seating.