I did some .22 rim thickness sorting.
I use the Hornady gauge, but I found that to get consistency I needed to permanently JB Weld it to the calipers. So, I sacrificed a $20 Harbor Freight set. I found it is easier and faster to mount the set up to my bench. Just use a 3/4 " block and a soft jaw squeeze clamp.
https://i.imgur.com/oaoB43U.jpg
I've also cast a few hundred Mihec 22 NATO boolits