As folks in posts above have mentioned, each bullet's ogive shape is different, and therefore you will get a different measure per different bullet brand/weight/shape.
RE the term "ogive": I too have been puzzled by the use of this terminology, because I perceive it being used differently, depending on the context of the article or gear measurement system I am reading about (such as a comparator tool). So I did some googling and found some Wikipedia links that were helpful.
This article in Wikipedia describes various ogive shapes used in projectile nose cone designs: https://en.wikipedia.org/wiki/Nose_cone_design
Scroll down and you will find the descriptions and images of tangent and secant ogives (common in modern bullet designs), plus several others.
My conclusion after reading this is that "ogive" is the overall shape, not a point of specific diameter on the shape. The ogive is the entire shape from the forward edge of where the bearing surface ends to the bullet tip. The Wikipedia article describes the geometry equations for how the various ogive shapes are drawn. Very interesting stuff.
Where the bullet touches the lands, or is driven into the lands a little via the jam method (e.g. Erik Cortina's video), is somewhere along the ogive shape, but its not a specific point or diameter on the nose (ogive shape) of the bullet that is common to all chambers. Where it touches the lands, is a function of the angle of the chamber leade's grooves, and the shape of the bullet's ogive, for a given bore diameter.
The bullet comparator may measure a different point than the lands touch. In the 280 AI, the lands ramp on the leade angle into 0.277 bore diameter (on the SAAMI chamber spec). My Hornady bullet comparator "28" measures 0.275" diameter. Therefore that comparator will stop on the ogive when it hits that 0.275" diameter.
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