.30-378 Weath. Mag. Load Data & Reloading Guide
Also known as: .30-378 Weatherby Magnum, .30-378 Weathby Mag, 7.62×74mm Weatherby
About .30-378 Weath. Mag.
The .30-378 Weatherby Magnum was introduced in 1996 by Roy Weatherby as a high-performance cartridge designed for long-range shooting and big game hunting. It was developed to combine the velocity and flat trajectory of the .378 Weatherby Magnum case with a .30 caliber bullet. This combination allows it to deliver outstanding ballistic performance while maintaining manageable recoil for experienced shooters.
The key technical characteristics of the .30-378 Weatherby Magnum include a case length of 2.625 inches and an overall length of 3.6 inches. It typically operates at pressures up to 65,000 psi, which contributes to its impressive muzzle velocities, often exceeding 3,400 feet per second with appropriate loads. Reloaders can utilize various bullet weights ranging from 150 to 220 grains, allowing for versatility in load development depending on the intended use.
In terms of ballistic performance, the .30-378 Weatherby Magnum achieves exceptional flatness in its trajectory, making it an excellent choice for long-range hunting and target shooting. Its high velocity minimizes wind drift and retains energy effectively over extended distances. This caliber is particularly popular for hunting large game such as elk and moose, where its high energy transfer upon impact is critical.
For reloaders, the .30-378 Weatherby Magnum offers the advantage of a wide range of available components, including various bullet types and powders. This flexibility enables the development of tailored loads that can optimize performance for specific situations, whether for hunting, competition, or long-range precision shooting. The ability to fine-tune loads for different bullet weights also allows reloaders to maximize accuracy and terminal performance, making this caliber a compelling option for those looking to enhance their shooting experience.
Technical Drawing

Technical Specifications
Start Calculating to Develop your own Load Data for .30-378 Weath. Mag.
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Start CalculatingStandard Load Data — .30-378 Weath. Mag.
Select your desired cartridge and bullet weight below to access the corresponding load table. From there, you can choose any listed load recipe and transfer it directly into the ballistics calculator for further refinement, optimization, and precision tuning.
.308 | 170gr | Prvi Partizan FSP
.308 | 125gr | Nosler Ballistic Tip Hunting
.308 | 170gr | Sako Blade
.308 | 168gr | Speer MHP BTHP M
.310 | 125gr | Speer HP TNT
.308 | 180gr | Sako Hammerhead
.308 | 210gr | Berger VLD Hunting
.308 | 210gr | Nosler RDF
.311 | 100gr | CutEdge ESP Raptor
.307 | 110gr | Prvi Partizan SP RN
.311 | 123gr | CamPro FCP
.311 | 123gr | Sellier & Bellot FMJ
.308 | 175gr | SAKO Blade
.308 | 180gr | Swift Scirocco
.308 | 200gr | Reichenberg Subsonic
.308 | 200gr | Sako Hammerhead
.308 | 200gr | Sierra GameKing
.308 | 200gr | Lapua Subsonic
.300 | 220gr | Berry's Spire Point
.308 | 85gr | MAKER Tipped expanding
.308 | 88gr | Inceptor SRR
.308 | 115gr | AERO SUB,- smax:11.40
.311 | 123gr | Lehigh Defense Controlled Chaos
.308 | 110gr | Winchester Hollow Point
Frequently Asked Questions
The maximum pressure for .30-378 Weath. Mag. is 63,817 psi | 4,400 bar.
.30-378 Weath. Mag. typically uses a Large Rifle Magnum (LRM) primer.
The case capacity of .30-378 Weath. Mag. is approximately 133 grains of water (H₂O).