AR-15 Ammunition - A Primer

.223 Remington and 5.56 NATO and an explanation of .223 Wylde

This is what DALL-E thinks the cross section of a rifle cartridge looks like. AI has a bit to learn about rifle cartridges.

The word cartridge comes from the French word “cartouche.”  Originally, cartouche was a term that French soldiers applied to the paper cartridges in use in the late 1500’s – yes, the late 1500’s.

Eventually, paper cartridges were replaced by metallic cartridges. Modern breech loading firearms almost exclusively use metallic cartridges. The components of a modern metallic cartridge are the case, a primer, propellant (gun powder), and a bullet. In speech, cartridge means the complete assembly. “Round” also means the complete assembly. Bullet, case, primer, and powder are references to one of the components.

Anatomy of a Cartridge (.223 Remington or 5.56 NATO)

Externally, .223 Remington and 5.56 NATO cartridges are nearly identical. In the picture below, you see a .223 Remington cartridge manufactured by Remington. The dimensions shown in this picture are from SAAMI (Sporting Arms and Ammunition Manufacturers Institute[1]).