Hornady® Superformance™ .300 Winchester Magnum 165gr CX™ ammo is a long-range centerfire rifle cartridge. Features Hornady's CX (Copper alloy eXpanding) bullet design for superior stopping power on big game targets. Premium reloadable brass casings deliver smooth operation and reliable feeding performance. Other features include non-corrosive boxer primers and clean-burning powders and propellants. 20 rounds. For optimal results with a gas-operated semi-auto firearm, it is recommended that all Hornady Superformance ammunition be paired with rifle-length gas systems and barrel lengths of 20" or longer. Any barrel and gas configuration of less than 20" is best served with the installation of an adjustable gas system, especially if firing suppressed. Made in USA.