Using the Seating Depth Comparator
I will now give an example of use of the Comparator in conjunction with an OAL gauge.
Using the OAL gauge and case, I have gently seated a bullet into the lands, tightened the stop screw and carefully removed it from the chamber. Now I insert the bullet into the Seating Depth Comparator until the shoulder is seated in the opening of the tool. Zero the dial indicator. The tool is now zeroed at the lands.
A displayed positive number when checking a seated bullet from here would indicate a bullet seated into the lands, while a negative displayed number would indicate a bullet seated off of the lands. .010 would be .010 into the lands and -.010 would be .010 off of the lands. Alternatively, you may zero the dial indicator with no cartridge in the tool and use the number displayed when checking cartridges as a basis for comparison between many loaded cartridges.
Please note that displayed readings should only be used for comparison within a single lot of bullets.