StevieP Wrote:Shilen's 18" mid tactical barrel is six groove, one in nine twist.
What bullet weights is 1:9 best suited for?
The 1:9 twist is a common twist for .264 cartridges like the 264 Winchester Magnum prior to current trend of using long sleek bullets with high BC for long range shooting. I have two 1:9 twist 6.5 Grendel barrels and they are both accurate with bullets from 85 grains to 125 grains. My Son in Law has a 22 Lothar Walther 6.5 CSS with 1:9 twist which is accurate with 129 grain SST ammo. Supposedly the longer barrels do a little better with the slower twist.
Berger has a stability twist calculator which is useful for determining if your twist is suitable for a particular bullet. If your goal is to shoot long range especially with bullets over 123 grains the 1:9 twist barrel is not optimal. Ive shot my 20 1:9 twist Shilen barrel to 1000 yards with 123 grain bullets and am satisfied with its performance.
https://bergerbullets.com/twist-rate-calculator/