Without something to use as a comparator you are only guessing. If you have a head space gauge you can perhaps come up with a bushing that fits over the neck, allowing the bushing to stop pn your shoulder. Then measure a reference distance from the base of your case to the opposite end of the bushing that contacts the shoulder that establishes your head space. All this is assuming you have a caliper and are comfortable using it.
If this works out for you you can also use the same bushing to reference your Go- head space gauge. Id shoot for .004 clearance give or take .002".
Another option is a case gauge or a comparator neither will do you much good without a head space gauge or fired case for comparison.
https://www.whiddengunworks.com/product/case-gauge-3/
https://www.whiddengunworks.com/product/...ump-gauge/
How precise do you wish to get? for your consideration a Whiddnen click adjustable full length bump die.
https://www.whiddengunworks.com/product/...ing-kit-2/
If this works out for you you can also use the same bushing to reference your Go- head space gauge. Id shoot for .004 clearance give or take .002".
Another option is a case gauge or a comparator neither will do you much good without a head space gauge or fired case for comparison.
https://www.whiddengunworks.com/product/case-gauge-3/
https://www.whiddengunworks.com/product/...ump-gauge/
How precise do you wish to get? for your consideration a Whiddnen click adjustable full length bump die.
https://www.whiddengunworks.com/product/...ing-kit-2/