Starline 270 Winchester Rifle Reloading Brass - 50 Count - Starline Brass prides itself on producing the highest quality brass case available. Their brass is comprised of 70% copper and 30% zinc and is vertically drawn during the manufacturing process which results in more uniform wall thickness. Cases are annealed between each draw to ensure consistent metallurgy in all lots. Each brass case is hand inspected to guarantee the highest quality possible.