High Quality Content by WIKIPEDIA articles! The .416 Rigby or 10.6x74mm was designed in 1911 by John Rigby & Company of London, England as a dangerous game cartridge and is the first one to use a bullet with a diameter of .416". The rifles, as built by John Rigby & Co., were initially made up on Original Magnum Mauser actions although in later years, some were made on standard length actions, a perfect example being the rifle used by legendary professional hunter Harry Selby. Other famous users of the cartridge were Commander David Enderby Blunt, John Taylor and Jack O`Connor.