The .257 Weatherby Magnum is a high-velocity quarter-bore magnum cartridge introduced in 1945, long associated with Roy Weatherby himself as a personal favorite. Known for blistering speed and a very flat trajectory, it is prized for open-country big game.

The .257 Weatherby Magnum was introduced in 1945 as part of Roy Weatherby's line of high-velocity magnum cartridges, and it was reportedly his own favorite. It takes the quarter-bore (.257 caliber) and pairs it with a large magnum case, producing one of the fastest .25-caliber cartridges ever made — its identity is built on sheer velocity. Ballistically the .257 Weatherby drives quarter-bore bullets at exceptionally high velocity, producing an extremely flat trajectory that makes it well suited to long shots on deer, pronghorn, and similar open-country game, as well as varmints with lighter bullets. The high velocity delivers dramatic performance but comes with significant muzzle blast and the accelerated barrel wear typical of cartridges driving bullets this fast. It occupies a distinct niche among the Weatherby line as the speed-focused quarter-bore, favored by hunters who value flat trajectory and reach in open terrain. Like other Weatherby cartridges, its ammunition is more specialized and expensive than mainstream rounds, consistent with its premium, high-performance positioning. Today the .257 Weatherby Magnum is used for open-country big-game hunting, varmint hunting, and long-range target shooting, with availability centered in Weatherby and a growing number of other rifles. Its combination of class-leading quarter-bore velocity and a very flat trajectory is why it has held a devoted following for decades.

General information about this caliber — not a recommendation for this specific firearm.