.30-378 Weatherby Magnum

The .30-378 Weatherby Magnum is a cartridge introduced by Weatherby in 1996 that uses the same case as the previously existing .378 Weatherby Magnum and .460 Weatherby Magnum, necked down to a 30 caliber (7.62 mm) bullet. It is offered with bullets between 165 and 200 grains (10.7 g and 13.0 g) in factory loading, generating velocities able to exceed 3500 ft/s and muzzle energies over 4750 ftlbf. The cartridge was the product of a design/development effort of 1958-1959 between Mr William L. Strickland at the U S Army Ballistics Laboratory of Redstone Arsenal Alabama and Roy Weatherby. The research development contract specified the development/production of a single shot rifle/cartridge combination which could provide a flat nosed and based, 80gr and 100 gr projectile velocity of 6000 ft/s. 35mm high speed motion picture cameras were used to photograph the performance and impact results of various projectile alloys while impacting different types of armor plate. The rifle was removed from the stock and mounted in a machine rest, the armor plate targets were 10' in front of the muzzle. The results of this testing have helped the Army in the development of effective battlefield armor and armor penetrators used on the battlefield today. In later years, projectiles fired in this rifle were studied and designed for hunting game at very long distances, and for marksmanship competition in excess of 1000 yd.

Performance
The .30-378 case holds as much as 120 gr of powder without requiring a compressed load. This allows the cartridge to develop more energy than the .300 Remington Ultra Magnum and .300 Winchester Magnum, especially when handloads are used.

Note: Using the bullet weight and muzzle velocity in each cartridge that provided the maximum muzzle energy. Data for the .30-378 is from. Loading data for all other cartridges can be found at

Note: data for the .30-378 from Weatherby (which tracks closely to what handloaders can achieve based on loading data at. Data from the .30-06 is also from Hodgdon. The initial data used is included here for anyone who cares to run the calculations themselves.

Costs
Rifles built by Weatherby are available in .30-378, and ammunition is significantly more expensive than other cartridges, with ammunition costing upwards of $120 USD for a box of 20 rounds as of 2012. Weatherby offers this caliber in several versions of its Mark V rifle. Due to the strong recoil a round of this energy can create, all Weatherby rifles offered in this caliber include a muzzle-brake. SAKO offered the TRG-S in .30-378 Weatherby at one time but now lists the TRG-S as an "Old Model" and is no longer available.