Re: bullet runout
First, your terms seem off.
You will not measure bullet runout, because there isn't any.
Your tool will likely measure case runout, and/or loaded ammo runout, off the case shoulders, or mouths, or off the bullet bearing or nose.
A standard for runout measurements(in my view) is Sinclair's. You set the case on bearings between the web and shoulder. While rolling the case, your measure in runout is read from an indicator you set on the round. The runout seen will grow from shoulder to the bullet tip.
The case head rides against a peg to prevent for/aft movement while rolling, and many use an eraser to roll cases with less error in measurement(due to slightly rocking the case off the bearings). This is where bearings are better than V-blocks.
I consider Sinclair's the standard because any runout in loaded ammo will atleast show up using this tool. In fact, it either shows runout as it is, or else amplifies it beyond what it is. Depends on what you specifically measure & where, and what is causing the variance.. But no irregularity gets by unnoticed.
It doesn't mask runout like the bullet straightening types out there. These support loaded rounds by the ends only, measuring nearest one end, while allowing the majority of runout(caseborn) to swing in the wind -unindicated.
While you can measure runout quit low with these, drop em on a Sinclair to see what you really have left.
Do you have a pic of your tool?