The 338 Remington Ultra Magnum (RUM), introduced in 1999, was a companion introduction with the 7mm and 375 RUMs, the trio completing (to date) Remington's family of full-length Ultra Magnums. The 338 RUM is based on the unbelted 300 RUM necked up to 338-caliber. It is a full-length (2.850-inch) magnum requiring a 375 H&H-length action. Although not as fast as the 338 Lapua Magnum its fat case has greater capacity than the 340 Weatherby Magnum, thus is capable of greater velocity. It is an extremely powerful and hard-hitting cartridge, but acceptance has been limited...probably due to its substanstial recoil. It is an excellent long-range elk cartridge, with factory loads including a 225-grain bullet at 3020 feet per second and a 250-grain bullet at 2860. Remington has remained the primary supplier of both rifles and ammunition.
