.338 Remington Ultra Magnum

.338 Remington Ultra Magnum

.338 Remington Ultra Magnum
Type Rifle
Place of originUSA
Production history
Parent case.300 Remington Ultra Magnum
Case typeBeltless, rebated, bottleneck
Bullet diameter
Neck diameter
Shoulder diameter
Base diameter
Rim diameter
Rim thickness
Case length
Overall length
Case capacity
Rifling twist1-10 in (254 mm)
Primer typeLarge rifle magnum
Maximum pressure
Test barrel length: 26"

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 ranks third after the .338 Lapua Magnum and .338-378 Weatherby Magnum in cartridge-case capacity.

Because this cartridge already operates at very high pressures (65,000 PSI), Handloaders cannot give significant improvements over factory ammunition as many handloaders have done over the years with more conventional, lower pressure rounds.

See also


  • .338 Remington Ultra Magnum reloading data at accuratepowder.com BROKEN
  • .338 Remington Ultra Magnum case diagram