Have built two of these. In testing and load development, the Berger 180g Hunting/VLD was stable in that twist rate. Berger recommends a 1-9 twist rate for that bullet. At .659 BC and moving at 2800fps the Berger delivers very impressive ballistics at 1000. The first STW I had was from Devin Sinner and was a Savage 114 Ultra with a magnum contour 24" barrel. Shot extremely well with the Berger. The others used barrels from the Savage custom shop and were 26" varmint contour 1-9 twist. The STW excels over the 7MM Magnum with heavier bullet weights. IMHO it is easier to obtain great accuracy out of the STW than the 7MM Mag. Sure does burn a bunch of powder!