The Hornady Superformance Rifle Ammo 5.56 NATO 55 gr CX SPF delivers the Superformance series' standout combination of long-range speed and controlled expansion with Hornady's CX (Copper Alloy eXpanding) bullet, giving hunters and range shooters a high-velocity 5.56x45mm NATO option that drives a 55 gr projectile at roughly 3175 fps and about 1231 ft-lbs of muzzle energy for flatter trajectories and reliable terminal performance; built with brass cases and made in the United States, this ammunition suits small- to medium-game hunting, varmint work, and precision practice where retained weight and consistent expansion matter, and it feeds and functions well in modern sporting rifles chambered for 5.56 NATO. The SPF designation identifies the Superformance propellant profile that increases velocity potential compared with conventional loads, translating to improved downrange performance and tighter group consistency at extended ranges important when dialing holdovers or when decisive terminal effects are required. With copper-alloy expanding bullet construction, notable muzzle energy, and a manufacturer-backed reputation for ballistic consistency, this Hornady Superformance 5.56 NATO load is a solid choice for hunters and shooters seeking high-velocity, expanding rifle ammunition from a trusted brand.