The .223 Remington cartridge is a popular centerfire rifle cartridge that was first introduced in the 1960s. It was designed by Remington Arms in collaboration with the United States military and was intended for use in the M16 rifle. Today, the .223 Remington is used in a wide variety of rifles, from bolt-action hunting rifles to semi-automatic sporting rifles.

The .223 Remington bullet has a diameter of .224 inches and a length of 1.76 inches. It typically weighs between 40 and 77 grains, with the most common weights being 55 and 62 grains. The bullet is known for its flat trajectory and high velocity, which make it ideal for long-range shooting. It is also a popular choice for varmint hunting and target shooting, as it produces minimal recoil and is relatively affordable.