The 300 Blackout (300 AAC Blackout) was developed by the US Advanced Armament Corp. as an upgrade to the 5.56 NATO that would be comparable to the 7.62x39 AK-47 round.  Specifically, the 300 Blackout is designed to operate both supersonic with a long barrel, and subsonic in a short barrel configuration with an optional suppressor.  The result is a 30 caliber bullet between 78 and 125 grain and a casing filled with fast burning powder (no muzzle flash) that fits 30 rounds in a standard 223/556 STANAG magazine.  The 300 Blackout on the AR15 platform operates effectively with barrel lengths between 4.5" and 20", nearly silently with subsonic ammunition and a suppressor.  The 300 Blackout uses the standard 5.56/.223 Bolt Carrier Group.

Any 300 Blackout Upper Receiver we sell can be configured to your specifications before adding it to the cart.  We offer matched muzzle devices, rails, bolt carrier groups, magazines, and charging handles to make your 300 Blackout Upper Assembly turn key and ready to shoot out of the box.

AR15Parts.com components are sourced from top US manufacturers including Aero Precision, Anderson Manufacturing, Ballistic Advantage, 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 individually on our website.

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