223/556 NATO AR15 Rifle Upper Assembly / 223/556 NATO Complete Rifle Upper for AR15

556 NATO (5.56x45) is the cartridge used by the US Military M4 carbine and many other NATO weapons.  The 223 Wylde chamber was developed to allow 223 Remington and 556 NATO ammunition to be fired from the same barrel.  Both rounds are effective in the rifle configuration across a wide range of barrel lengths from the 14.5" standard on an M4 carbine up to 24".

AR15Parts.com components are sourced from top US manufacturers including Aero Precision, Anderson Manufacturing, Shaw Barrels, Swan Machine, Wilson Arms, Wilson Combat, ZRO Delta, and others. Each upper assembly has options to select Rail, Muzzle Device, Bolt Carrier Group (BCG), Charging Handle, and Magazine. Additional parts are available on our website.

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