I'm an amateur cartridge collector, like to dig through the ever-present boxes of random ammo at gun shows, been doing it for decades. I run across surplus 30-40 Krag loaded ammo from time to time, usually dated 1917 or earlier. I've learned over the years to check, because more often than not the necks are cracked. This is unfired ammo, so I assume they were just made wrong, poor quality brass or something?