So, you are trying to make the body of the case longer by fire forming? On belted magnum hunting chambers I stay between Go and Go plus .003" and let the forward portion of the case body expand to the chamber when fired. I have been using Go to Go plus .003" for nearly 30 years and had no complaints. Re-sizing hasn't presented any problems as I always recommend to adjust to enough 'bump' for easy chambering. It's a hunting rifle and needs to chamber the 2nd round easily for a follow-up, if needed (I never get to shoot at 'stupid' animals where I might get a 3rd shot if I've screwed-up the first 2).That's exactly what I have been doing. Sometimes I just over-think things and I want to be sure I'm doing the right thing. I read in another post where Cohunt mentioned that Manson no-go gauges are .006" longer than the go gauges. I'm using a .007" shim and adjusting headspace (remage) until it will only close with some effort applied. All seems well. My ADG brass seems to take 3-4 firings to get to length at the datum unlike the WW brass I was using. I just thought I'd throw it out there to confirm/deny my method. I don't want to use the belt for headspace.