The Imperial Magnums .300, .311, .338, .360 and 7mm were introduced circa 1991 by the Imperial Magnum Corporation, Osayoos, British Columbia, Canada after buying the IMPERIAL trademark from Canadian Industries Limited and later IVI (Industries Valcartier Inc.) when they (IVI) moved away from the civilian ammunition market. It is based on the 404 Jeffery case and the shortage of quality 404 brass during the early 90’s lead to the demise of the Imperial Magnum Company. They were taken over by North American Shooting Systems (NASS) who renamed the cartridges as Canadian Magnum.