6.5mm bullet development continues apace, this time courtesy of Weatherby, which has championed the SAAMI acceptance of a new loading, the 6.5-300 Weatherby Magnum. SAAMI acceptance is a major step towards the general acceptance of a loading outside of “wildcat” status.

With SAAMI acceptance, the specifications for the chambering are made public, which typically then leads to larger adoptance of the cartridge. By going public, manufacturers of reamers, buttons, broaches, and other firearms components are able to fully understand the loading including critical tolerances to then make compatible offerings. Most critically, ammo and barrel manufacturers are able to make products with little risk of incompatibility across the market.

Specifically, the 6.5-300 Weatherby Magnum was developed to push super-slick 6.5 loadings to extremely high velocities. To quote Weatherby, “Never has a 6.5mm bullet gone faster!” This may be completely true, as the SAAMI spec loading can push a 127 grain pill past 3500 feet per second.

Weatherby has commercial loadings and unprimed brass available. The cartridge is not for the light of wallet. Commercial ammo is $95/box for 20 rounds and the factory-new brass is $42 for 20. (Here’s to hoping that SAAMI acceptance will drive down costs!)

Additional details can be found at Weatherby’s website and through ballistics charts below :

6.5-300 BALLISTICS

Velocity

Energy

Trajectory