I think the above response is quite correct. You're only measuring to the ogive so the bullet's length doesn't really matter. It's not touching anything. One thing I found about using the Stoney Point OAL guage is there is a slight learning curve. At first I'd take 3 measurements and get 3 different readings. After a while I started doing everything the same way especially with the applied pressure. Now I find it works like a charm. Best wishes.

Cal - Montreal

Without a ogive guage or comparitor the stoney point guage is not worth much. Most caliber I have, have so much freebore, it doesn't matter.

Even with the comparator, I must calibrate for every different bullet I use. THe ogive is not the same shape for different bullets. However, I do use one bullets data for a starting point for another, but this did cause trouble on one occasion with the new bullet running into the lands.