[DAN CARROLL]

I noticed hornandy makes both a concentricity tool and a bullet comparator. What are these and what do they do?

[rcmodel]

The concentricity tool measures the run-out, or "wobble" on a loaded round. The straighter the bullet is aligned in the case, the better in theory, it should shoot.

The Comparator measures seating, or OAL of the cartridge based on the bullet ogive, rather then bullet tip.

It is a more precise way to measure seating depth because not all bullets out of a box are the same length.
But the ogive shape should be.

rc