The .375 Ruger is not the 8x68 case. It is larger, as in .532" at the head, not .522". The .375
Ruger's case will give slightly greater capacity than the .375 mag, but in a modern-type case which handles our powders slightly better than the longer sloping case.
: Necked to .416, it would deliver about the same ballistics as the .416 Remington, as the capacities would be very close - within a grain or two. The .416 "Ruger" would fit in standard .30/06 length acitons, perfectly, allowing about any bullet seating length one wanted as it has a 2-5" case.