It likely depends on the the angle that the throat of the chamber is cut by the reamer. I've got a factory .222 that likes the bullet well off the rifling, but it's got a fairly steep angle. A shallower angle might like the bullet closer to or into the rifling. I sort of think that it doesn't depend so much on caliber as the bullets and throat angle, at least with .22's and 6 mm's.
The only way to see what your rifle likes is to try various seating depths and shoot them. The rifle will tell you what it likes.
