The .300 Remington Ultra Magnum made its debut in 1999, followed by the 7mm Remington Ultra Magnum and in 2002 the .338 & .375 Remington Ultra Magnum were introduced.  The Remington Ultra Magnums, joined an increasingly popular trend toward beltless, magnum-sized cases. Headspacing on the shoulder of the case, rather than the use of a belt, promotes better accuracy due to precise bore alignment. At 300 yards the 7mm Remington Ultra Magnum produces 24% more energy than the standard 7mm Remington Magnum and 12% greater energy as well as a flatter trajectory than the 7mm STW.  When tested by Remington at 200 yards, the .300 Ultra Magnum delivered nearly 18% greater retained energy than the .300 Weatherby Magnum and almost 27% greater retained energy than the .300 Winchester Magnum. The velocity and energy performance of the Remington Ultra Magnum cartridges comes from an innovative case design. Modifying the .404 Jeffery case with a rebated rim to fit magnum cartridge bolt-faces, increased body taper, with a .30 caliber sized neck, Remington’s resulting case allows about 13% more internal capacity than the .300 Weatherby – it allows a similar sized ballistic advantage. The .338 Remington Ultra Magnum is one of the most powerfull 338-caliber rounds available, delivering 25% greater muzzle energy than the .338 Winchester Magnum and retains a flatter trajectory all the way out to 500 yards, technical details of this cartridge are identical to the .300 Remington Ultra Magnum. The .375 Remington Ultra Magnum is one of the hardest-hitting .375 chamberings available, with 23% more energy at the muzzle and delivers more energy at 200 yards than does the .375 H&H Magnum at 100 yards.