For high quality, Winchester Unprimed Brass Rifle Cartridge Cases - 100/box are preferred by many hunters and competitive shooters. During manufacturing, cases go through annealing to produce the correct hardness that holds the bullet securely in place but also provides flexibility when firing. Because of this, the cases may have a light stain near the neck.Sometimes the cases arrive with imperfect mouths due to manufacturing or shipping. For reloading, the mouth needs to be resized, as well as chamfered and deburred. If wanted, an expander ball can be pushed through the neck in line with the sizing die.