Greetings,
I just bought a Hornady OAL gauge (using it w/ Hornady's bullet comparator) to measure OAL at the bullet's ogive. I measured 2.305" to seat bullet against the lands and seated some 150gr Nosler BT at 2.285" and they are too long to fit in the detachable magazine (Tikka T3 Lite). I then measured a factory Federal 150gr SP at 2.190" that does fit in the mag and I have shot as good as a 1" group at 200yds.
I have read about seating the bullet anywhere from .005" to .020" off the lands for best accuracy.
Why so much difference?

If you are loading for hunting, use your magazine as the longest bullet to seat to fit in it.

No point in trying to adjust the distance to the land, as you are restricted by your magazine.

Saeed is right.
And don't worry. Your rifle should shoot just fine..tj3006

if you have shot enough of the federal 150's at the 2.190 length to know they are accurate in your rifle you should try this length for your reloads. once you find the distance from the lands your rifle likes it will probably shoot most bullets well at that seating depth.

Saeed is right. The thing to do now is find the bullet/powder combination your rifle likes best.

I have a .270 that shoots best with 130 gr. bullets .100" off the lands, go figure. One of the most accurate rifles I have is a .308 that shoots 125 gr. bullets very well but if seated to touch the lands they wouldn't even be in the case. I like to start experimenting with new loads .015 to .020" off the lands but if that isn't possible don't assume you won't get good accuracy. As others have said see what works in your rifle.

Saeed is correct..today most all factory guns limit your seating depth and most all factory guns have longer throats, so bullet jump is declared a villain by many experts..I have not found that so in many cases.

Sounds like a very familiar question!

Just part of the great .308 design roger

On seating bullets off the rifling, it depends on the rifle. Some like the bullets touching, others like them off the rifling a bit. This is something you have to experiment with to find what your rifle likes.
Leo