Factory-new brass comes unprimed and is always sold from the same lot. Winchester is the only U.S. ammo manufacturer that makes its own cases starting from raw materials through to the finished product. Their precise engineering and tight tolerances help ensure you get high-quality brass that chambers positively. This clean, unprimed brass withstands the stresses of multiple load-fire-reload cycles, and the brass in each bag comes from the same production lot for optimal consistency in your finished ammo.