At what range?
Keep in mind, I have no data to prove this, just hear say.
I have spoke with several barrel manufacturers about this very issue. Over half of them recommended a faster twist to stabilize anything higher than 168. According to them, the 1:12 was good up to the 168gr for ranges greater than 500 yards.
This is what I have been told. Do what I did and call up some barrel mfg. It only takes a few minutes and most are pleased to help someone out.
I'm fairly sure that Krieger got quite tired of me calling and bugging them about my first build. I figured, who better to get my info from than those that
make their living by such products i.e. rifle barrels.
I run a Krieger with a 1:10 on a Surgeon 308.
I have another Rem 700/Krieger chambered in a 308 that has a 1:10 and it groups well past 500.
Some folks will scoff at a 1:10 twist on a 308, but I have several paper targets that would argue that it is just fine. I shoot Berger 175gr BT LR T's and 155.5gr Match Fullbores.
Again, I am just passing along information that was given to me by other manufacturers.