Cartridge Talk: Final Results on 6.5X300 Wby. Testing

If you have been following our test results with the New 6.5X300 Wby cartridge, you already know we have tried slowing the twist rate down to improve accuracy.  In our last post, we showed how accuracy improved slowing the rate of twist from the factory 1:8 to a 1:9.

While this has improved accuracy, results have still been inconsistent, especially with different factory loads.  Our last group average with the 1:9 twist was a .544 with the 127 LRX ammunition.  Recent rifles have failed to maintain this average.

Since we guarantee 3-shot, 1/2″ groups at 100 yards with factory ammunition, and have not consistently seen this result with any of the twist rates we have tested, we are removing the 6.5X300 Wby. from are cartridge list.  We will not build our rifles, perform Deluxe Accurizing, or offer our Use What You have program for this chambering.

Our overall conclusion is that the cartridge is simply too overbore to produce consistent accuracy.

We would love to see Weatherby offer the 6.5 based on the 270 Wby. case size.  We believe this would solve all the accuracy problems associated with this cartridge and would also greatly extend barrel life.

If you are still looking for a very flat shooting hunting cartridge, we strongly recommend the 28 Nosler, 7mm STW, and new 6.5 PRC cartridges.


  • curtducker
    Posted at 08:05h, 22 August

    Try loading the 6.5 in a 30-06 case. I believe it would be a more stable round if so and still have velocity and power. Velocity would probably still be in the low 3,000fps range and energy would be in the upper 2,000 range….

    • Matt Bettersworth
      Posted at 08:41h, 26 August

      Yes, a better round for sure. The ole 264 Win. Mag. works great as does a 270 Wby. necked down to 6.5. All much better high velocity 6.5’s.