The 6.5-300 Weatherby Magnum (6.5-300 WM) introduced by Weatherby in 2016, is the fastest factory 6.5mm cartridge in history! Based on the big .300 Weatherby Magnum case necked down, the 6.5-300 WM is a full-length belted magnum; its 2.85-inch case requires a .375 H&H-length action. Weatherby factory loads include a 127-grain Barnes LRX and 130-grain Swift Scirocco, both at around 3500 fps. The 6.5-300 WM is overbore capacity so barrel life will be fairly short, and performance is best with a 26-inch barrel. Its flat trajectory and long-range performance are spectacular, and the cartridge can take advantage of both the new aerodynamic 6.5mm bullets...and the upurge of interest in the 6.5mm. From a hunter's standpoint the 6.5-300 WM has surprisingly mild recoil, and one quickly notes how fast the bullet gets there! Interestingly, Roy Weatherby considered a 6.5-300 but decided 1950s bullets couldn't handle the velocity. With today's bullets the time for this super-fast 6.5mm has arrived! —
Craig Boddington