The .223 rifle cartridge was designed by Remington for hunting small game in the 1950s. Always lightweight and accurate, it has been redesigned several times for higher power and deeper bullet penetration. Its most recent transformation occurred in 1980, when it was remodeled into the 5.56x45mm NATO. This new cartridge is nearly identical to the .222, the main difference being that the 5.56X45mm uses a new metal jacket bullet with a 7-grain steel core to better penetrate armored targets (such as helmets). It is a trusted rifle for both combat and hunting. 

The .223 Remington cartridge is a popular round for a variety of sports, from hunting to competitive shooting. It is a smaller round than many other rifle cartridges, so shooters will find it easier to carry and aim. The .223 Remington is commonly used for small game hunting and target shooting, but it can also be effective for self-defense.