5.56 NATO Ammo Prices

The Army adopted it with the M16 in 1964, NATO stamped it in 1980, and the AR-15 turned it into the rifle cartridge of American life.

The bulk market runs on two military patterns: 55 grain M193-style and 62 grain green-tip M855-style, much of it Lake City brass or NATO-spec production from overseas. The pressure rule is short and worth keeping straight: a 5.56 chamber eats both 5.56 and .223, while a .223 chamber should stay on .223. Steel-cased imports fight brass hard on price.

This caliber moves in 500 and 1,000-round cases, and the per-round spread between a small box and a crate is wide enough to fund your pricey optics habit. Compare before you buy. That's the whole game.