Home › Browse Calibers › .378 Wby. Mag.
Common uses: Dangerous Game, Big Game
| Type | rifle (centerfire) |
| Typical load | 300gr Weatherby Select Plus Hornady DGX Bonded (Dangerous Game Expanding / RN-EX) |
| Muzzle velocity | 2925 fps |
| Muzzle energy | 5701 ft-lb |
| Published G1 ballistic coefficient | 0.275 |
| Case length | 73.8 mm |
| Overall length | 95.3 mm |
| SAAMI max pressure | 65000 PSI |
| Range (yd) | Velocity (fps) | Energy (ft-lb) | Drop (in) |
|---|---|---|---|
| 0 | 2925 | 5698 | -1.5 |
| 100 | 2585 | 4450 | 0 |
| 200 | 2271 | 3435 | -3.7 |
| 300 | 1978 | 2606 | -14.3 |
| 400 | 1711 | 1949 | -33.8 |
| 500 | 1473 | 1445 | -65.2 |
At 1,000 yards, .378 Wby. Mag. (300gr at 2925 fps, 100 yd zero, standard conditions) has a modeled come-up of about 55.1 MOA / 16.0 MIL, retaining 893 fps (subsonic).
| Range (yd) | Velocity (fps) | State | Drop (in) | Elev (MOA) | Elev (MIL) |
|---|---|---|---|---|---|
| 300 | 1978 | Supersonic | -14.3 | 4.6 | 1.32 |
| 400 | 1711 | Supersonic | -33.8 | 8.1 | 2.35 |
| 500 | 1473 | Supersonic | -65.2 | 12.5 | 3.62 |
| 600 | 1273 | Transonic | -112.8 | 18.0 | 5.22 |
| 700 | 1122 | Transonic | -182.0 | 24.8 | 7.22 |
| 800 | 1021 | Subsonic | -278.6 | 33.3 | 9.67 |
| 900 | 949 | Subsonic | -408.6 | 43.4 | 12.61 |
| 1000 | 893 | Subsonic | -577.3 | 55.1 | 16.04 |
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 .378 Weatherby Magnum is a hard-hitting dangerous-game cartridge that drives heavy .375-caliber bullets at velocities well beyond standard .375-bore rounds, making it a choice for the largest and most dangerous African game as well as heavy plains game. Its reputation rests on flat trajectory and tremendous downrange energy, but that performance comes with punishing recoil and muzzle blast that demand a heavy rifle and an experienced shooter. The generous case burns a large powder charge, so barrel wear and ammunition cost run high, and factory ammunition and rifles are comparatively specialized and expensive. In practice it is a purpose-built big-bore hunting cartridge rather than an all-around choice, favored by hunters who want maximum reach and stopping power in the .375 class and are willing to tolerate its recoil. It remains a flagship of Weatherby's magnum family and the foundation of several of the company's largest cartridges.
Roy Weatherby introduced the .378 Weatherby Magnum in 1953, developing it from his African safari experience to surpass the performance of his earlier .375 Weatherby Magnum. Rather than necking down an existing case, he built a large new belted magnum case with the double-radius shoulder characteristic of the Weatherby line. That oversized case went on to serve as the parent for later Weatherby cartridges, including the .460 Weatherby Magnum and the high-velocity .30-378 Weatherby Magnum. Its large powder charge was also a factor in Federal's development of the 215 Magnum primer to ignite it reliably.
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