Introduced in 2022 the 338 WBY RPM (rebated precision magnum) maximizes the magnum potential of the lightweight Mark V 6 Lug action. The goal was to fit a large caliber bullet into a lightweight backcountry rifle that could take down all of North America's big game. The 338 RPM is based off of the 6.5 RPM necked up to accept a .338 caliber bullet. The case features a large body diameter, low body taper, and 35-degree shoulder creating a larger powder capacity, leading to higher velocities.