The 338 WBY RPM (Rebated Precision Magnum) is based on the Weatherby 6.5 RPM necked up to accept a 338 caliber bullet. The 338 RPM was designed to take advantage of Weatherby 6-Lug action to get magnum performance in a 5lb rifle. The large body diameter, low body taper, and 35-degree shoulder mean that case capacity is greatly increased, leading to higher velocities.
CARTRIDGE SPECS
Bullet Diameter: .338 (8.6mm)
Common Reference: 338 Caliber
Max Case Length: 2.57”
Production Start: 2022
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.
The 338 RPM is an extremely efficient cartridge and maintains velocity even with 18” barrels which are featured on the Mark V Backcountry lineup.
Type - Barnes TTSX
Bullet Weight (grains) - 185
B/C (G1) - .432
Muzzle Velocity (Ft/Sec) - 3100
Muzzle Energy (FT LB) - 3947
