Some first hand experience:
Cracks and/or sharp folds, not dents but folds, in the shoulder of new cases.
Improper annealing, leading to neck cracks after one or two reloadings.
Slag in the brass material itself, like a bullet cast from dirty metal not fluxed and skimmed.
Primer pockets well out of spec for depth and/or excessive radius between the bottom and side walls of the pocket.
Flash holes well off center and/or punched through at odd angles with excessive burrs inside the case.
New case mouths far out of square.
