If I may...What is a set to gauge? I am wiating for my first switch barrel to arrive and planned on using a sized piece of brass to set the headspace. Am I going to run into problems here? Do I need to remove the ejector?

This is a wildcat cartridge (6.5 CSS or Grendel) and go-no go gauges are not readily available. Which iss why I planned on using the brass.

Thanks