The 30-378 Weatherby Magnum is a.30 caliber, belted, bottle-necked rifle cartridge that was designed in response to a military contract from the United States Army in 1959. Roy Weatherby created it for a government contract as an anti-personnel/anti-material military cartridge. This white-hot cartridge is based on a 378 caliber cartridge that has been necked down to 30 caliber and loaded with powder. It comes factory loaded with bullets weighing between 165 and 200 grains (10.7 g and 13.0 g), producing muzzle speeds of over 3,500 ft/s (1,100 m/s) and muzzle energies of over 4,750 foot-pounds force (6,440 J).
The cartridge went on to achieve world records for accuracy while still undisclosed to the public, including the first ten 10X in 1,000 yards (910 m) bench rest shooting.
For the impact of light bullets on armor, the US Army's Redstone Arsenal required a rifle cartridge that could develop 6,000 ft/s (1,800 m/s). The.30-378 Weatherby Magnum was capable of reaching speeds of almost 5,000 feet per second (1,500 meters per second). The 30-378 Weatherby Magnum was able to attain over 5,000 ft/s (1,500 m/s), however, while using a slower burning and denser propellant, the .30-378 Weatherby Magnum surpassed the US Army’s requirement of 6,000 ft/s (1,800 m/s). Later, the 30-378 Weatherby Magnum was put to the test for long-range hunting and marksmanship competitions of over 1,000 yards (910 m).
The 375 Remington Ultra Magnum which is abbreviated as the 375 RUM, is a rifle cartridge developed by Remington Arms in 2002. It's a beltless, rebated rim cartridge that's made by necking up a.300 Remington Ultra Magnum case to.375 caliber with no additional modifications. The 338 features a slightly shorter case than the 338 RUM in order to maintain a comfortable cartridge overall length (COAL) inside the confines of the Remington M700 rifle magazine.
The.375 RUM has had little popularity since its inception. Nonetheless, the.375 RUM is a powerful cartridge, capable of pushing a 300 grain (19 g) bullet at 2760 ft/s (840 m/s), producing 5070 ft·lbf (6.88 kJ) of energy. This bullet's muzzle velocity may be increased to a maximum of 2950 ft/s (900 m/s) by handloading, producing 5800 ft lbf (7.9 kJ).
Large, thick-skinned game should be the primary target for the 375 Remington Ultra Magnum. It has the power to kill any land mammal and can do it over a great distance because of its rapid velocity. However, such performance comes at the cost of a high recoil: this cartridge can create a ferocious 80 ft lb (108 J) of recoil in a sporting-weight rifle weighing 8 lb (3.6 kg) (approximately 3.5 times that of a .30-06.) Most shooters' capabilities go well above this. There is a good assortment of.375 in (9.53 mm) bullets that are suitable to the.375 RUM's high velocity, and boat tail rounds assist to increase the usable range even more.
