Your next question may very well be, "How do I determine the distance to my lands, the throat lead?" Well, there are several different methods for doing this. There is the majic marker method, aka the smoked bullet method, there is the split neck method, the partial neck sized method, ect, ect.
These methods have two things in common. 1. they all work, 2. they are a real big pain in the kiester. When you are ready to start loading rounds tailor made to your rifle's freebore, I would suggest spending a few bucks and getting one of these, a
Stoney Point O.A.L. gauge They are not expensive.
It's common practice to work up a load with the projectile .010" from the lands. After a good load is found, more hairs may be split by adjusting that bullet jump, in slightly, or out.
To measure those projectile and loaded cartridge lengths more accurately, I would suggest a Stoney Point bullet comparator I don't know if you have noticed, but bullet tips are far from uniform, notoriously so. The worst offenders, believe it or not, are HP Match bullets. Bullets that have the jackets drawn on by a die get their jackets drawn on from the base forward. The HP formed by the leftover jacket is usually different, bullet to bullet. Softpoint designs are not much better. Long ago it was thought that the bullet tip was very critical to accuracy. They found out it is not. The shape of the tip has an effect on B.C., but it is the bullet's base that is super critical with respect to accuracy. One small scratch or dent on the bullet base will have a negative effect on accuracy.
Because the bullet tips are very seldom uniform, it is best to measure a bullet from the base to the ogive to get an idea of the uniformity of a particular lot/box of bullets or loaded rounds, with respect to length. That data would be for comparsions only, of course. It would not replace any load data.

If you decide on a Stoney Point product, shop around, you will probably get a better price than the factory offers.