I just received some headspace gauges I rented for my 6.5/284 build. I previously set the headspace with a piece of brass resized in my die with an added piece of tape measuring .002" in thickness to the face of the cartridge. I just checked the headspace with the no go gauge and it will only close about a 10th of the rotation required.

Here is where I can't decide what to do next.

A: leave everything alone

B: reset the barrel with the go gauge

the reason I ask is that I have a couple of nosler loaded ammo and the bolt will close on those cartridges with an added .004" thickness op tape added to the face. I'm thinking these rounds are slightly undersized. I tried to measure them vs my resized brass but I can't determine where the difference is.