|.340 Weatherby Magnum|
|Place of origin||United States|
|Produced||1963 to present|
|Parent case||.300 H&H Magnum, full length|
|Case type||Rimless, bottlenecked with venturi shoulder|
|Bullet diameter||.338 in (8.6 mm)|
|Neck diameter||.366 in (9.3 mm)|
|Shoulder diameter||.495 in (12.6 mm)|
|Base diameter||.513 in (13.0 mm)|
|Rim diameter||.530 in (13.5 mm)|
|Rim thickness||.048 in (1.2 mm)|
|Case length||2.82 in (72 mm)|
|Overall length||3.6 in (91 mm)|
|Case capacity||98 gr H2O (6.4 cm3)|
|Primer type||large rifle magnum|
|Source(s): Weatherby |
The .340 Weatherby Magnum rifle cartridge was introduced in 1962 by creator Roy Weatherby to fill the gap between the .300 Weatherby Magnum and the .378 Weatherby Magnum, and in response to the .338 Winchester Magnum released in 1958.
The .340 Weatherby Magnum uses the same .338 in. diameter bullets as the .338 Winchester Magnum, but it does so at greater velocity than its Winchester competition. Reloaders may have trouble matching the published Weatherby velocities as Weatherby factory ammunition is loaded to maximum specifications. Weatherby no longer loads the 250gr. round-nose cartridge pictured but continues to load the 250 gr. Spire Point and 250 gr. Nosler Partition. Weatherby has also expanded their factory loads including Nosler Ballistic-tip and Barnes TSX bullets complementing the powerful cartridge. Currently A-square is the only other factory ammunition producer of the .340 Weatherby Magnum, which has led to limited popularity of the caliber. In field tests the .340 clearly outperforms the 300 Ultra mag, .338 Win mag. and even rivals the larger .375 H&H, providing a much flatter shooting and harder hitting performance.
This cartridge is powerful enough for even the largest North American game and is suitable for most African game as well.