 It is considered the most powerful commercial .416 cartridge, besting the Remington, Rigby and Ruger .416s by a velocity of .Unlike earlier Weatherby cartridges which were designed by Roy Weatherby, this cartridge was designed by his son Ed Weatherby.Beginning in the 1960s and through the 1970s, safari hunting in Africa was on the decline, and in turn demand for big-bore cartridges waned.