It seems most guys run the 175 grain bullets in the 308 Win.
Why are most people running a 1/10- 1/11 twist???
I actually suspect there are more 1:12s than 1:10 from manufactures....at least numerically
1:13 will work if you drive them very hard or live/shoot at altitude (above 1000 feet). However, if you don't drive them hard (>2500 fps) they may not stabilize (may not).
A 1/12 or 1/11.25 seems like a better choice. I have always heard it is better to over stabilize than under stabilize. It seems though that shooters should run a optimium twist rate. If this does not hold true we would all shoot with the fastest twist rate avaliable.
I am about to have a 308 WIN built. I do not plan on going heavier than a 175. The 175 is my first choice and the 155 my second.
The guys who shoot long distances for score (like PALMA, F-class) want just enough stability so that the bullet will nose down during the downward decent to the target. This can tighten up groups from 800 yards and out, at some expense to the up close groups inside 300 yards. This is a specialized shooting arena and every little bit helps.
For tactical purposes this may not be the ideal trade off, but if you are shooting only one load in your gun and develope a complete set of dope for both gun and load, then it remains viable. However, if you like to experiment with loads and bullets, the faster twist rate leaves so little on the table accuracy wise, and desensitizes the gun to so many effects, it is typically the better trade-off for general purpose shooting.
1:13 a specialized twist rate for long distance shooting
1:12 a general purpose twist for bullets up to 175
1:11 a general purpose twist for bullets up to 200
1:10 a specialized twist rate for bullets above 130 and below 220