Mykey, using nosler partitions or ballistic tips I usually seat .020 or so off the lands and have not had an accuracy issue with either bullet. Make sure you use a quality OAL gauge like something from Stoney Point or Sinclair. With some finicky calibers .010 could make a big difference. Only one way to find out and that is by experimenting ...load up 10 rounds at one OAL and try them and then if no go try a little farther away. Reloading bullets in a Browning A bolt I left the bullet at factory OAL and it made no difference in accuracy since I was using optimum powder for the bullet in question. I believe that Powder is the key component to accuracy. This is assuming that your cases are sized correctly with quality dies.. trimmed evenly..flash holes deburred(Unless Norma) ... same primers and proper primers for the caliber etc etc. Hope that helps