I shot My new/old Marlin 27S for the first time yesterday useing new Rem cases. I shot about 20 rounds and noticed that two of the cases split just above the head. So im thinking something is maybe wrong with the chamber.
I get home and examine the chamber and measure the best I can with a telescoping bore guage and so far it looks okay. Then I get to looking at case dimentions in several manuals and find that case head measurement vary from .347 to .349. My Rem case heads measure .343 and that is what the LEE die sizes them back to.
The Rifle is in very good condition overall and looks to have been not fired in the last 50 years and the bolt locks up tight. I may try a chamber cast next.
Any other thoughts guys. I did measure the fired case at the split and it is .350.