I got some LC 7.62 cases to reload that were prepped when I purchased them. Out of 100-120 rounds that I fired 35 had partial head separations . The initial length was 1.627 The fired length was as long as 1.650 on these cases . They will not rechamber in my rifle. I also fired some of my LC match and some OFV factory loads. These averaged 1.638 to 1.641. These also will not rechamber in my rifle, they will if I push down on the bolt lug with my thumb. How could the cases be so much larger than my chamber is? These were in all likely hood MG fired brass. Is it possible that they went back to the size they were when fired in the MG ? My HS is on the long side at 1.636 but passes the field test gauge.