From Wikipedia, the free encyclopedia:
"The .338 Remington Ultra Magnum is a .338 caliber rifle cartridge introduced by Remington Arms in 2002. It is a beltless, rebated rim cartridge based on the .300 Remington Ultra Magnum case shortened .090" loaded with a .338 caliber bullet. The .338 Remington Ultra Magnum is second only to the .338 Lapua Magnum and .338-378 Weatherby Magnum in cartridge-case capacity.
Handloaders should note that this cartridge already operates at very high pressures (65,000 PSI), significantly higher than standard rifle cartridges and higher even than most "magnums." This cartridge should not be "hot rodded," as many handloaders have done over the years with more conventional, lower pressure rounds."
.338 Remington Ultra Magnum. (2008, June 29). In Wikipedia, The Free Encyclopedia. Retrieved 19:50, March 22, 2009, from http://en.wikipedia.org/w/index.php?title=.338_Remington_Ultra_Magnum&oldid=222385879