I opened up a mew thread on this same subject, wasn't sure if it should be on here or a new one as it is about headspace and shoulder bump. This is the post though-
So I got the proper device to measure relative headspace (hornady comparator is why I say relative). I had some brass around that had been shot with just neck sizing way to long, some I can barely close the bolt. The measurement I got for that was 3.636, Then I measured some Fed. M80 7.62×51 and got 3.630. Heres where my confusion sets in. I went and shot some reloads I had already loaded by just setting my FL sizer up as instructed by lee. Those are measuring 3.631. Should I go with the old overused brass measurement, or the stuff I fired today? 3.636 or 3.631? I'm probably just gonna go buy new brass and start from scratch till I find the numbers I need unless someone has a better idea of what measurement I should use. Thanks
I ended up going and getting some nosler brass and the measurement for it is 3.629