The .416 Taylor’s big advantage was that it delivered .416 Rigby ballistics (well, almost) in a standard Mauser action. Finn, being almost pathologically frugal, saved on freight charges to Africa by having just the one rifle. In those days, switch-barrel bolt-action rifles were possible only through rather complex custom gunsmithing that wasn’t cheap, but I assume Finn, then writing for the NRA, got a deal on it.
Anyway, that was my first real exposure to such mechanisms, and we spent a good deal