You may be right. I have two 6.5 calibers, a Creedmoor and a 6.5X284 Norma. The Creedmoor with slower velocity has 1-8 twist while the 6.5X284 has 1-9 twist. The 140 Bergers supposedly should have a 1-8 twist, but both rifles stabilize them, and the 140 Amax. The added velocity of the 6.5X284 has to be why they stabilize with a 1-9 twist. I don't know what the twist rate is, but the new 264 Win Mags also stabilize the 140 Berger VLDs. I would think the Weatherby would stabilize the 105 bullets.