The .338 Weatherby RPM (Rebated Precision Magnum) is a rifle cartridge developed by Weatherby Inc. Introduced in 2020, it is designed for high performance in lightweight rifles. The cartridge features a rebated rim, which is narrower than the case body, and allows for a slimmer action while maintaining the capability to handle higher pressures.
The .338 Weatherby RPM is known for its flat trajectory and powerful performance, making it suitable for hunting big game like elk, moose, and bears. It can achieve muzzle velocities exceeding 2800 feet per second with considerable energy retention, which translates to effective long-range performance. The rebated rim design helps manage recoil and ensures reliable cycling in lightweight bolt-action rifles.
Weatherby designed this cartridge specifically for their Mark V Backcountry and Backcountry Ti rifles, aiming to provide hunters with a high-power, long-range option without the added weight usually associated with magnum cartridges. This combination of power and lightweight design makes the .338 Weatherby RPM particularly appealing to backcountry hunters who need to hike into remote areas.