Chuck,
I understand the reasons for using headspace gauges, how to use the ones I have (disconnecting and removing the op-rod in order to hand-work the bolt), and why you need only the FIELD for an assembled rife in which the HS is known not to be too short.
I only own one type of HS gauges, they look like the base of a cartridge, have a blunt tip, and don't require bolt disassembly.
What does a HS gauge that would require bolt dissasembly look like?