Average Velocity: 3200 fps The .223 Remington cartridge and 55 grain projectile is by far the most widely used round for the AR-15 platform. This full metal jacket round is capable of firing in barrels labeled as 5.56x45mm NATO, .223 Rem, and .223 Wylde. On top of that, the projectile is the ideal weight for a wide range of barrel twist rates, 1-in-7, 1-in-9, and 1-in-8, are just a few examples of barrels that this round run accurately with. About our Ammunition All of our LAX ammo (except .50 BMG) is loaded on our own Ammo Load Mark X (pistol) and Mark L (rifle) loading systems. Freedom Munitions uses only premium components and performs a variety of quality checks during the loading process guaranteeing consistent performance round after round.