And without a straight edge stand the case gage with a protruding case head on a flat surface then with a feeler gage measure the gap between the case gage and flat surface, this helps when adjusting dies for sizing.
Bart B. ? there is nothing I covered that a bench rest shooter is not familiar with, there are those that have mistakenly shot 308 W (.388 extra head space) in a 30/06, what did they get? a 30/06 case with a very short neck, there are those that have shot 8X57mm in an 8/06 (.129 extra head space), what did they get? a short neck 30/06, and the misunderstood or flawed experiment by Hatcher? it is said he moved the shoulder forward about? 1/4 inch (sound familiar) .125 thousands and fired 30/06 ammo in the chamber with extra head space with out separating the case body from the case head, what did he get? he got formed cases for his modified chamber, now if Hatcher took those modified cases and sized them back to minimum size and repeated the experiment he would have shortened the life of the case, and the life of the rifle and the life of the shooter, and at the same time there are claims he moved the shoulder forward with a go-gage and the action of the bolt cam, I believe that claim is a blind of two stories.
Back to 'AGAIN' I do not move the shoulder forward by firing, I move the shoulder forward by forming, that is the reason I never pass a bargain on 280 new/used Remington cases, the 280 R shoulder is ahead of the 30/06 shoulder by .041 thousands, so it is a matter of technique, method, skill, knowledge and a few tools and time to form 30/06 cases with a shoulder moved forward .014 to .015 thousands to form a case for the Eddystone with head space, I know head space of the chamber before I size the case, but this is something bench rest shooters learned to do before they became bench rest shooters.
I made a set of gages for the 30/06 and sent them to a collector in Bradford, PA. he called me and informed me he had what he thought was an Eddystone M1917 that had not been issue, except for the .016 head space.
I meant to say .016 head space because that is what it is, .016 thousands and it is beyond the field gage by .002. Keeping up! a factory loaded case from the store is .000, that is .005 under a go-gage chamber, that puts the go-gage chamber at +.005, the no-gage chamber is +.009, the field gage is +.014, or .014 over a factory loaded round or +..009 over a go-gage etc.. that is what I said, the rifle in Bradford PA., has .016 head space, my M1917 has .016 head space IF I shoot factory or full length ammo in it, the advantage to a long chamber? cases fired in it can be sized (not formed) to fit long chambers, like +.008, .010, where do those numbers come from, these numbers can not be obtained from a go-gage or a no-go gage, both are fixed, they either go or do not go, that is good enough for most but I want to know 'by how much' because I cut my chamber using gages that start at -.012 under factory ammo, that is .017 under a go-gage.
I also sent another set to North Carolina, the collector, reloader gun builder called and and asked me how I came up with the technique/method, I asked him if he had a lathe, he said yes, I asked him if he had a mill, he said yes, I then explained to him it was easy, he says he takes a few of the gages with him to gun shows, shops or answering adds, and no one objects, in thinking back I sent him two sets made two different ways.
F. Guffey