Update 26/05/24: Made the slot where the caliper goes a bit wider to fit a wider range of calipers, and also made the overall measuring length 1.00inch.

Update 22/05/24: Now updated with space for a nut so you can tighten it to the caliper, just insert a pause print on the layer where it closes. Fits M3 screw and nut such as these https://www.aliexpress.com/item/1005006841125709.html?

Seems to do the job, gives consistent and repeatable measurements. However FDM printers are not accurate enough to be used for absolute measurements (such as comparing to SAAMI spec sheet), only comparative (such as bumping back the shoulder when resizing). Much cheaper than the Hornady headspace gauge kit!

Printables Tags: reloading