The term 'Weatherby' is one that has been closely synonymous with speed. The.257 Weatherby Magnum is part of the Weatherby series of hunting cartridges, which are distinguished by its trademark double-radius shoulder, brass belt, and large case capacity.
The.257 Magnum was Roy Weatherby's favorite of all the cartridges he developed in the Weatherby series. It currently ranks third in the Weatherby cartridge series.
The.257 Weatherby Magnum was one of the earliest standard-length magnums, manufactured by shortening the.375 H&H Magnum case to roughly 2.5 inches (64 mm). It's a commercial flat-shooting cartridge that can fire a 115 grain (7.5 g) Nosler Ballistic Tip bullet at 3,400 feet per second (1,036 meters per second) while producing 2,952 feet per pound of force (4,002 J) of energy.
The 257 Wby. Magallowable .'s pressure of 65,000 psi is one of the reasons it travels so quickly. It's a better round than 800-yards from a ballistic standpoint.
The.257 Weatherby's limits are essentially up to the shooter. It works best on light to medium weight games weighing between 20kg (44lb) to 150kg (330lb). The top limit of 180kg (400lb) is still considered safe. They were used to kill a rhinoceros by Roy Weatherby himself just to show that it can be done. With that said, the .257 Weatherby Magnum will perform over and above what you’d typically expect from such a bore diameter.
The.257 Weatherby Magnum cartridge is a tremendously powerful cartridge that is unlike any other.257 diameter cartridge in that it can employ a huge target area up to substantial ranges.