I have the same problem with Ruger rifles. They just do not fit me. Same with the new Sako 85 in Kodiak. They seem to point fine and I like the stock design and feel...until I squeeze the trigger on live round. They all seem to hit harder than the caliber would suggest. The RSM in .458 Lott and .416 Rigby especially. 6 or fewer rounds of either was all I cared to fire. Yet a CZ 550 in .458 Lott, I could shoot 19 rounds and feel less beat up than with the Ruger. I fired some 600 gr hot handloads and they felt stiffer than the other loads but totally fine in the CZ. Did not dare to try them in the RSM. Even the Ruger Scout in .308 hit harder than any other .308 I have had and it was kind of heavy for such a small rifle. In the end I just wrote it off as Rugers not fitting me at all for some reason. CZs in the same caliber even with their "club like" new stocks seem to be way more comfortable for me. So I imagine those that find Rugers comfortable would find CZ perhaps unpleasant. Just as an example. Sorry for not having anything to add to that .416 vs .375. No hunting experience with either. But I'd be inclined to pick .375 for most shooting. Only if going after buffalo or similar I'd probably want something bigger. I'd choose .458 Lott just because I really liked it and it gives even bigger set up from the .375, but .416 Rigby seems to pack a wallop, so I believe those that say it is quite another animal compared to the .375.