The Hard-Hitting .257 Weatherby Magnum

By and large, I am not of the “sniper” mindset when it comes to hunting North American big game. That is to say, I believe in getting as close as possible before taking the shot.
That said, when I moved to southern Arizona several years ago I wanted a rifle that would reach across big, deep canyons and kill the diminutive, super-sneaky Coues whitetail and mountain muleys, as well as tune up flat-country pronghorn when necessary. Thus I acquired a Weatherby Vanguard MOA rifle chambered for Roy Weatherby’s all-time favorite, the .257 Weatherby Magnum.
It has proven to be a great choice.

The .257’s Pedigree

Designed in 1944—a year before Roy Weatherby went into the commercial gun business—the .257 Weatherby Magnum is a .25-caliber belted bottlenecked cartridge. It is one of the original standard length magnums developed by shortening the .375 H&H Magnum case to approx. 2.5 inches. It is one of the flattest-shooting commercial cartridges available today.
One of its most popular factory loads features the 115-grain Nosler Ballistic Tip bullet with a muzzle velocity of 3,400 fps, which generates 2,952 ft.-lbs. of kinetic energy (K.E.)—comparable muzzle energy to the .30-06 and .35 Whelen.

The .257 Weatherby Magnum shares the same cartridge case as both the .270 and 7mm Weatherby Magnums. The .30 Super Belted Rimless H&H served as the direct parent cartridge for the case design, and served as the forerunner to the standard length magnum cartridges such as the 7mm Remington Magnum and the .338 Winchester Magnum.
There has been some speculation that Roy Weatherby may have used the full length .375 H&H Magnum case if he had slow burning powders available today when the cartridge was designed. The shortening of the case allowed for the more efficient use of the slowest powder of the day, IMR 4350—a powder that would not have provided any great advantage for such cartridges as the .257 or .270 Weatherby Magnums if such cartridges utilized the full length H&H case.
Today, IMR 4350 is considered almost too fast a burning propellant for the cartridge which comes into its own with the slowest burning powders now available. These include IMR 7828, H4831, RL22, RL25, AA3100, and Viht N160 and N165, among others.

500-Yard Accuracy

Bullet weights for the .257 Weatherby range in weight from 75-120 grains, with the most popular for big game hunting weighing 100-120 grains. It is a hunting cartridge and has not been, for the most part, adapted into any target shooting discipline.
In fact, care must be taken at the range to allow the barrel to sufficiently cool between groups or you’ll find that accuracy will suffer, and barrel life will be shortened. When going to the range I always bring a jug of ice water and a towel, and use it to cool the barrel after every 5-shot group. I also clean the barrel after every 10 shots.The cartridge really shines when and where shooting at game over long distances is required. It is ideal for small to medium-sized deer, pronghorn, and other small ungulates. I have also used mine when hunting predators like coyotes, bobcats, and fox, though because the barrel heats up extremely quickly it is not a good choice where high-volume shooting is taking place.


Blogger news