.425 WR dos have a rebated rim - it also has a low shoulder and long neck, making it quite a bizarre looking cartridge. The ballistics, however, are pretty impressive: around 2400 fps velocity and over 5000 ft/lbs with a 410 grain bullet. It was a succesful calibre in its day (being introduced in 1909) and there were even a few doubles built to take it!

The short case length means that a standard Mauser action can accept it and the rebated rim will fit a bolt originally designed for something like .30-06. All this means that good dangerous game rifle can be built around a relatively inexpensive action. Kynoch are even making ammunition for it. The only reasons I can see for its lack of success are that the odd shaped cartridge puts people off and the proliferation of more modern cartridges like .458 Lott et al. Shame.