Case gauge/headspace mic.

[montana]

What are your thoughts on using them?

[the rifleman]

I have reloaded for over 20 years, and never bothered with them. If you have serious concerns about headspace I would have a gunsmith check the rifle out.

Now you should get a caliper! The digital ones are nice, and easy to read. You'll need this for checking case length, and trim length. Also when setting up the seating depth, if you want to maximize the accuracy. They can also be used on a fired case to a degree to check headspace.

A micrometer is good for checking for pressure signs, as they can measure to .00001, where the caliper is usually good for .0005 only. Depends on the unit I guess.