The 5.56×45mm NATO (official NATO nomenclature 5.56 NATO, commonly pronounced "five-five-six") is a rimless bottlenecked centerfire intermediate cartridge family developed in the late 1970s in …

Oct 23, 2025 · 223 vs 556: What’s the Difference? The cartridge cases of the 223 Rem and 5.56 NATO appear identical on the outside, but 556 cases can have minutely thicker case walls.

Developed in the late 1950s by the U.S. Army, 5.56mm ammo was designed to be lighter and more versatile than previous .30 caliber rounds. Officially adopted by NATO in 1980, it became the …

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America’s favorite cartridge, the 5.56 offers a wide range of loadings, proven performance, and a host of capable Springfield Armory firearms to fire them. Whether you want a rifle or a pistol, there’s a …

Feb 5, 2025 · Yes, there is a difference between 5.56 and 5.56 NATO ammunition, albeit subtle yet significant, primarily in pressure and chamber specifications, potentially leading to safety concerns …