The optimal twist rate for a specific bullet will be dependent upon a number of factors to include length, profile, velocity, etc. Consider that a standard non-premium 7mm factory barrel will be manufactured to accommodate a range of bullet weights up to and including 175 grains and that calls for a 1:9 twist.
Longer bullets generally need a faster rate of twist to stabilize while shorter bullets can be spun slower however, within reason, are just fine with a faster rate of twist so you need to go with the heaviest (longest) bullet you intend to shoot. Barrel makers don't even agree on what is the optimum twist, Lilja says 1:12 for 120 and 1:10 for 140 as well as 160. So perhaps 1:11 is optimum for 140s but since they don't sell 1:11 7mm barrels that makes the 1:10 their choice for 140s. From a bullet manufacturer, Berger recommends a 1:11 for their 140 Match VLD
For a T/C rifle and not a benchrest, match quality, target rifle, I wouldn't be willing to pay any premium just to get a non-standard, slower twist barrel, but if all things were equal (quality, price, delivery time, etc.) I'd go with the 1:11. BTW all of T/C's 7mm barrels are standard at 1:9
Brian
