how do we check headspace on .22?
I have used Plastigage to check headspace on my CZs. Basically it is a piece of plastic extrusion of a controlled diameter that you put on the face of your bolt. By closing the bolt you "squish" the plastic and based on the width of the collapsed extrusion the supplied scale gives you a measurement of the gap. It is sold in automotive supply stores (about $10 if I remember correctly). I use green (gives you measurements between 0.025 and 0.076 mm) or red (0.051 and 0.152 mm).