[Discussion] 25 Weatherby RPM: Compact .25-Cal Magnum Built for Long-Range Precision

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Weatherby Launches the 25 Weatherby RPM Cartridge

Weatherby has officially introduced the 25 Weatherby RPM (25 WBY RPM), expanding its Rebated Precision Magnum (RPM) cartridge lineup. The new .25-caliber cartridge is designed to deliver magnum-level performance in a compact, efficient case, emphasizing flat trajectory, high velocity, and long-range capability without the bulk of traditional belted magnums.

Design Philosophy and RPM Series Context

The 25 Weatherby RPM follows the core design principles of the RPM family, which focus on maximizing ballistic efficiency through a rebated-rim case and modern geometry. By eliminating the belt and optimizing internal volume, the cartridge aims to provide consistent performance while fitting into standard-length magnum actions. Weatherby positions the 25 RPM as a solution for shooters seeking extended effective range in a lightweight hunting or precision rifle platform.

Rifle Compatibility and Action Platforms

Rifles chambered in 25 Weatherby RPM will be built on Weatherby’s Mark V action, including six-lug variants engineered to handle high-pressure magnum cartridges. Supported models include the Backcountry, Backcountry Ti, and other Mark V configurations designed for lightweight strength and accuracy. The cartridge will also be compatible with Weatherby’s Model 307 rifles, such as the Alpine MDT Carbon, expanding options beyond the traditional Mark V lineup.

Ballistics, Twist Rate, and Intended Performance

Weatherby lists a recommended 1:7.5-inch twist rate, reflecting the cartridge’s focus on stabilizing long, high-ballistic-coefficient .25-caliber bullets. This fast twist supports modern projectile designs intended for long-range shooting, contributing to the cartridge’s flat trajectory and retained downrange energy. Performance comparisons published by Weatherby place the 25 RPM among the faster and more efficient .25-caliber options currently available.

Reloading Considerations and Case Specifications

Weatherby describes the 25 RPM as particularly well-suited for handloaders. The cartridge features a 35-degree shoulder and a case capacity of approximately 72.5 grains of water, promoting efficient powder burn and consistent velocities. With a maximum overall length of 3.34 inches and 0.940 inches of seating depth, it accommodates long, streamlined bullets without sacrificing usable case volume. Compared to the 25 Creedmoor, Weatherby reports roughly 40 percent greater case capacity, translating to higher potential velocities. Weatherby has confirmed that unprimed brass will be offered alongside factory ammunition options.

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