What about cartridge overall length?
When I first started reloading (not all that long ago, which is probably pretty obvious) I would be pulling my hair out of my head trying to adjust the seating die so that all the finished cartridges would all be the exact same length. After a while, I had to be happy with them averaging out to be close to where I wanted them to be as long as they were within spec.
After some research, I learned that different types of bullets, different manufacturers, and just variations between one individual bullet and another made it impossible to get consistent measurements from bullet tip to case head. The recommendation was to use a comparator to measure off the ogive to get a more reliable number. Ok, so I can do that, but I havent seen a manual which lists any ogive to casehead length.
So if I have a manual calling for a 3.000" oal which is bullet tip to case head, and I have a comparator measurement of 2.650" which is bullet ogive to casehead, (made up #'s for sake of argument), I need to somehow "convert" the second measurement to what the book is looking for. My thinking is to seat a bullet until the tip to tip is equal to the data in the manual, then measure it with the comparator to come up with the ogive to casehead length. But what if the bullet I got my tip to tip measurement from is funky?
Improbably making this more complicated than it should be...
Now for combined over all length the hornady bullet comparator is only good if your actually trying to seat it at a specific point off the lands or duplicating a factory load.?
Ok, I have an idea about seating off the lands, etc. So maybe Im mistaken regarding finding overall length somehow other than measuring bullet tip to casehead?