.300 Remington Ultra Magnum

.300 Remington Ultra Magnum
.300 RUM cartridge
TypeRifle
Place of originCanada
Production history
DesignerRemington
Designed1999
ManufacturerRemington Arms Company
Produced1999–present
Specifications
Parent case.404 Jeffery
Case typecartridge, center fire primer, bottleneck
Bullet diameter.308 in (7.8 mm)
Neck diameter.344 in (8.7 mm)
Shoulder diameter.525 in (13.3 mm)
Base diameter.550 in (14.0 mm)
Rim diameter.534 in (13.6 mm)
Case length2.850 in (72.4 mm)
Overall length3.600 in (91.4 mm)
Case capacity110.2 gr H2O (7.14 cm3)
Rifling twist1–10"
Primer typeLarge rifle magnum
Maximum pressure65,000 psi (450 MPa)
Ballistic performance
Bullet mass/type Velocity Energy
150 gr (10 g) X 3,456 ft/s (1,053 m/s) 3,979 ft⋅lbf (5,395 J)
168 gr (11 g) BTHP 3,295 ft/s (1,004 m/s) 4,051 ft⋅lbf (5,492 J)
180 gr (12 g) BTSP 3,229 ft/s (984 m/s) 4,168 ft⋅lbf (5,651 J)
200 gr (13 g) SP 3,067 ft/s (935 m/s) 4,178 ft⋅lbf (5,665 J)
220 gr (14 g) RN 2,933 ft/s (894 m/s) 4,203 ft⋅lbf (5,699 J)
Test barrel length: 24" (610 mm)
Source(s): Accurate Powder[1]

The .300 Remington Ultra Magnum, also known as the .300 Ultra Mag, 7.62×72mm or .300 RUM, is a 7.62 mm (.308 inch) rifle cartridge introduced by Remington Arms in 1999. The .300 Remington Ultra Magnum is one of the largest commercially available .30 caliber magnums currently being produced. It is a beltless, rebated rim cartridge, capable of handling all large North American game, as well as long-range shooting. Among commercially produced .30-caliber rifle chamberings, the .300 Remington Ultra Magnum is second only to the .30-378 Weatherby Magnum in cartridge-case capacity.

  1. ^ ".300 RUM data at Accurate Powder" (PDF). Archived from the original (PDF) on September 28, 2007. Retrieved August 17, 2007.