Home › Browse Calibers › .340 Wby. Mag.
Common uses: Hunting, Big Game, Long Range
| Type | rifle (centerfire) |
| Typical load | 250gr Weatherby Nosler Partition |
| Muzzle velocity | 2941 fps |
| Muzzle energy | 4803 ft-lb |
| Published G1 ballistic coefficient | 0.473 |
| Case length | 71.8 mm |
| Overall length | 91.4 mm |
| SAAMI max pressure | 65000 PSI |
| Common twist rate | 1:10" |
| Range (yd) | Velocity (fps) | Energy (ft-lb) | Drop (in) |
|---|---|---|---|
| 0 | 2941 | 4801 | -1.5 |
| 100 | 2739 | 4165 | 0 |
| 200 | 2547 | 3602 | -3.1 |
| 300 | 2363 | 3099 | -11.7 |
| 400 | 2187 | 2654 | -26.4 |
| 500 | 2018 | 2260 | -48.4 |
At 1,000 yards, .340 Wby. Mag. (250gr at 2941 fps, 100 yd zero, standard conditions) has a modeled come-up of about 30.9 MOA / 9.0 MIL, retaining 1316 fps (transonic).
| Range (yd) | Velocity (fps) | State | Drop (in) | Elev (MOA) | Elev (MIL) |
|---|---|---|---|---|---|
| 300 | 2363 | Supersonic | -11.7 | 3.7 | 1.08 |
| 400 | 2187 | Supersonic | -26.4 | 6.3 | 1.84 |
| 500 | 2018 | Supersonic | -48.4 | 9.3 | 2.69 |
| 600 | 1857 | Supersonic | -79.0 | 12.6 | 3.66 |
| 700 | 1705 | Supersonic | -119.7 | 16.3 | 4.75 |
| 800 | 1563 | Supersonic | -172.4 | 20.6 | 5.99 |
| 900 | 1433 | Supersonic | -239.4 | 25.4 | 7.39 |
| 1000 | 1316 | Transonic | -323.4 | 30.9 | 8.98 |
Extended predictions beyond 500 yards are modeled from the same G1 engine — useful for initial DOPE, but outside the 500-yard manufacturer-table validation audit. Confirm with observed DOPE, especially near transonic.
A retained-energy reference only — not a shoot/don't-shoot distance. Real effective range depends on your accuracy, shot placement, bullet construction, and conditions. The ~1,000 ft-lb (deer-sized) and ~1,500 ft-lb (elk-sized) figures are commonly cited rules of thumb, not standards.
Your barrel, ammunition lot, and conditions will differ — always verify against the manufacturer's data and your own rifle.
The .340 Weatherby Magnum is a hard-hitting, high-velocity big-game cartridge favored for large and heavy game such as elk, moose, big bears, and open-country African plains game. It launches heavy .338-caliber bullets appreciably faster than the more common .338 Winchester Magnum, giving it a flatter trajectory and more retained energy for longer shots on large animals. That performance comes at the cost of stout recoil and muzzle blast, along with the higher ammunition prices and shorter barrel life typical of overbore Weatherby magnums. It has always remained a specialist's choice with a modest following rather than a mainstream seller, chambered primarily in Weatherby's own Mark V rifles.
Roy Weatherby introduced the .340 Weatherby Magnum in 1962, formed by necking up his .300 Weatherby Magnum case to accept .338-inch bullets. Like the rest of the Weatherby line, its lineage traces to the belted .300 Holland & Holland Magnum case, blown out to Weatherby's signature high-capacity, double-radius shoulder profile. It was developed partly as a response to Winchester's .338 Magnum of 1958, driving the same-diameter bullets substantially faster, and to fill the gap in Weatherby's own lineup between the .300 and the larger .378.
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