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The .338-378 Weatherby Magnum is a big, thirsty overbore cartridge, and brass that can stand up to those pressures is worth its weight in gold. Weatherby's BRASS333 unprimed cases are drawn by Norma Precision, the same Swedish outfit that has supplied Weatherby factory ammo for decades. That means you're starting your loads with cases that hold tight tolerances and consistent wall thickness right out of the box, which is exactly what you want when you're feeding a magnum this powerful.
These are new, unprimed cases with CNC-machined primer pockets cut to match-grade specs. That consistency in the pocket and flash hole helps with even ignition and uniform velocities, and it takes some of the guesswork out of your load workup. The .338-378 traces its roots back to a wildcat built by Elmer Keith and Bob Thomson in the 1960s, and Weatherby brought the commercial version to market in 1998. It's a belted, bottleneck design based on the .378 Weatherby parent case, so this brass is purpose-built for that beltline and the roughly 125-grain water capacity that makes the cartridge such a hard hitter.
With a case this large and pressures running high, quality brass pays off in the long run. Handloaders chasing the flat trajectory and heavy .338 bullets this cartridge is known for will appreciate having a reliable component to build around. Because it comes unprimed, you have full control over primer selection, powder charge, and bullet seating depth to tune loads for your particular rifle. Reach for magnum rifle primers and slow-burning powders to get the most out of this big case, and give your dies and trimmer a look before your first run since these cases run long.
Whether you're loading for elk, big bears, or long-range work, starting with proper Weatherby brass sets the tone for everything that follows.
These cases are drawn by Norma Precision, the same Swedish manufacturer that produces Weatherby's factory ammunition. Norma has a long reputation for tight tolerances and clean, consistent brass. That pedigree is a big part of why handloaders trust this component for a heavy-hitting cartridge like the .338-378.
They ship new and unprimed, so they are not loaded ammunition. You'll need to add your own primer, powder, and bullet to complete the round. That gives you full control over every part of your load recipe.
The .338-378 is a large overbore case that runs on magnum rifle primers and slow-burning powders to reach its full potential. Always start low and work up using published load data for the .338-378 Weatherby Magnum. Keep in mind this cartridge is not interchangeable with the older .338-378 KT wildcat, so use the correct data.
You'll want a set of .338-378 Weatherby Magnum dies and a case trimmer that can handle the long case length of just over 2.9 inches. Because this is a large-capacity magnum, checking case length before your first firing is a good habit. Proper case prep keeps your loads consistent and safe.
| UPC | 747115070749 |
|---|---|
| Manufacturer | |
| Manufacturer Part Number | BRASS333 |
| Caliber/Gauge | 338-378 Weatherby Mag |
| Product Type | Unprimed Case |
| Quantity | 20 Per Box |
| Shipping Weight | 1.0 |
| Style | Magnum |
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