For those of us who don't own the special Stoney Point tools here's a really quick , easy and quite accurate way that I have discovered to determine a reference point (lands contact) for seating depth of any given projectile in the throat of a rifle . 1) Seat a bullet well out (to the extent you are sure it will contact the rifling)in an empty , unprimed , resized case . 2) Remove the rifle bolt , insert the cartridge into the chamber and push it in firmly with your finger . 3) Carefully insert a cleaning rod into the muzzle and keep feeding it in slowly until you feel it contact the tip of the projectile . 4) Gently try to push the round out of the chamber .If the bullet is in contact with the lands some resistance will be felt . 5)Screw your seating die down a little and seat the bullet a little deeper . 1/8th turn changes seating depth around 10 thou. on my dies . 6)Repeat the test above . 7)Less resistance means less lands contact so screw the die down in smaller increments as resistance is reduced . Eventually you'll reach the point where the bullet is no longer in contact with lands and no resistance should be felt when pushing the round out of the chamber . 8) Using a vernier caliper measure the overall length of your loaded round and seating die and record for future reference . 9) Experiment with different seating depths to see what your rifle shoots best with . 10)You'll be surprised how easy it is to feel the resistance created when a projectile contacts the lands by only a few thousandths of an inch . Much easier than trying to visually find and measure rifling marks on a projectile .