From my research on the case dimensions of the Ruger, the case will have the same rim diameter of .532 as a standard belted magnum case. The base diameter of the bottleneck design in also .532 and does not have the belt. It should be a good performer equal to the .375 H & H or slightly better. The advantage of the Ruger is the shorter case can be chambered in actions not designed for 2.850" cartridges. However, I would not use the .270 and rebarrel. It would be almost as cheap to buy a 7mm mag or 300 Win mag and rebarrel. The .270 would need bolt face alteration and magazine follower changed. Rather that do the gunsmithing on the .270, keep it, rebarrel a used 7 mm mag to .375 Ruger and now you are ready for all game in North America. You could use the same 2 firearms with success in Africa on picked game and shots with the proper bullets and loads. Think about it.
Greg
Detente: an armed citizenry versus a liberal society