OAL data is not found in all manuals and I stopped recording it in my personal data long ago. The tip of a bullet is not a proper datum point unless you are using a tape measure to take the data.
On rifle ammo I have found it very easy to pull the firing pin and use the gun and bolt as a gage. Without the effect of springs I can feel the lands and bullet touching. I can decide from there what I want to try. I can go longer and force the bullet into the lands or I can go shorter. But I don't care where the point ends up as long as the finished round fits the magizine.
On pistol ammo I simply make sure I am off the lands with the bullet seated, and proper fit to the magizine.
OAL will not tell you both answers, only the magizine fit.