Quote:
“Head to Datum May get Shorter on Firing-Strange but True”
“Strange but true” I will assume that is a believe it or not option, if I assume correctly I choose not to believe it. The assumption a case gets shorter between the shoulder and case head is a retelling of a story that was not understood. The story tells of a smith/shooter/employ of the government at an arsenal. He moved the shoulder forward .080” and knew when he chambered a 30/06 round in his modified chamber he knew he was going to experience case head separation.
He did not quit trying, every time he chambered a round and fired he ejected Hatcher modified + .080” 30/06 cases. His cases did not shorten between the case head and shoulder, his cases shortened between the case head and case mouth, meaning his cases shortened in length. It was not assumed the case shortened, they knew the case got shorten, they just did not know the case also shortened.
they did not understand what happened, unlike me they did not measure before and again after. Back to Hatcher, he did not scribe his case, he assumed the shoulder moved forward, instead his shoulder was erased, flattened against the wall of the chamber, the shoulder on his new modified case was not there before he pulled the trigger, his shoulder on his fired cases were new shoulders, Hatcher became a fire former, had he scribed the case body/shoulder juncture he would have know his fired cases did not stretch between the case head and case body, had he scribed a line at the case body/shoulder juncture he would have noticed the line did not move, which means the case got longer between the case head and shoulder/datum, ( as in measured from Datum ).
Again, I form cases, years ago there was a case former forming cases from 30/06 military to anything 8mm57, 7mm57 etc., etc.. and selling the cases on EBay, the cases had small lines around the case, no one ask about the lines, I assumed no one knew how the line got there, the line appears on cases when they are formed, something like scribing a line.
Hatcher could have got the results he expedited, lie a friend that built magnificent wildcats, he said I was wrong, he chambered 30/06 cases to fire form and had 3 of 5 cases experience case head separation, I did not get upset, I did suggested had I been given an opportunity to fix the problem before he went to the range he would have gotten a different results, or, had I met him at the range I could have temporally made changes that would have allowed him to form his cases..
One more time, my friend and Hatcher were using the same rifle design, the 1903 Springfield. Hatcher did not experience case head separation.
“Brass may need 3 firings or more to fully form to the chamber” Not my brass, my brass has no memory of what is was before I pulled the trigger, then there is the three time firing before the case is fully grown, that goes right along with fire forming once and neck sizing 4 times ‘THEN! start over by full length sizing, back to fully grown after three firings, and or 4 neck sizing's. The case acquires a resistance to sizing, cases with a lot of resistance to sizing can have more resistance to sizing than the press has top overcome.
F. Guffey
