I met a man today who was shooting some Korean .30-06 Ball M2 he bought several years ago from Widener's. While I was watching him fire, one of the shots spit some small particles and a cloud of smoke from the breech of his M1 rifle. He had had an M-split; a case split that goes from in front of the case web through the primer pocket. Observation of the remaining cartridges of that ammo showed another case that was already split in the M region even before firing.
In US military practice, one failure of this type will get the whole lot condemned. It is my guess that this ammo was likewise condemned by the Korean military but it found its way into the civilian market and was sold cheap (for obvious reasons.)
The cartridges are in Korean marked packaging with .30 and M2 in English characters on the box. The headstamp is PS over 75. If you have any of this ammo, it should not be fired, and if you have cartridge cases from this ammo, they should not be reloaded.
Those of you who frequent other reloading forums may feel free to spread this info around.