.300 Blackout Complete AR-15 Upper Receivers

Complete .300 BLK uppers for your AR-15 make swapping out calibers simple. Re-use your 5.56 BCG and mags!

12 products

AT3 Tactical 10.5 Inch 300 BLK Complete AR-15 Upper Assembly - No BCG or Charging Handle

AT3™ 10.5 Inch .300 Blackout Assembled Pistol Upper for AR-15 – No BCG/CH

8 options

(13)

AT3™ 10.5 Inch .300 Blackout Pistol Upper for AR-15 - With Nickel Boron BCG and Mil-Spec CH

AT3™ 10.5 Inch .300 Blackout Complete Assembled Pistol Upper for AR-15 – With Nickel Boron BCG and Mil-Spec CH

AT3™ 16 Inch .300 BLK Assembled AR-15 Upper – 16 Inch Ballistic Advantage Barrel – No BCG/CH

8 options

(7)

AT3™ 16 Inch .300 BLK Complete AR-15 Upper - .300 AAC Blackout 16 Inch Ballistic Advantage Barrel - With Nickel Boron BCG and Mil-Spec CH

AT3™ .300 BLK 16″ Complete Assembled AR-15 Upper – With Nickel Boron BCG and Charging Handle

STNGR 8.5 Inch 300BLK Complete Upper w/ 7 Inch VYPR® Handguard, BCG & CH - 3 Colors

STNGR 8.3 Inch 300BLK Complete Upper w/ 7 Inch VYPR® Handguard, BCG & CH – 3 Colors

3 options

AT3™ Assembled Pistol Upper for AR-15 - .300BLK - 8.5" Barrel - 7" Free Float Quadrail - No BCG/CH - 3 Colors

AT3™ Assembled Pistol Upper for AR-15 – .300BLK – 8.3″ Barrel – 7″ Free Float Quadrail – No BCG/CH – 3 Colors

3 options

AT3™ Assembled Forged Pistol Upper for AR-15 - .300BLK - 8.5" Barrel - 7" Free Float Quadrail - No BCG/CH - 3 Colors

AT3™ Assembled Forged Pistol Upper for AR-15 – .300BLK – 8.3″ Barrel – 7″ Free Float Quadrail – No BCG/CH – 3 Colors

3 options

AT3™ .300BLK 16″ Assembled Forged Upper – 2A Basics ASAL 15" Handguard – No BCG/Charging Handle

AT3™ .300BLK 16″ Assembled Forged Upper – 2A Basics ASAL 15″ Handguard – No BCG/Charging Handle

AT3 10.5" .300 Blackout AR-15 JNL Ready Build Kit

AT3 10.5″ .300 Blackout AR-15 JNL Ready Build Kit

Radical Firearms 16" .300 Blackout Complete Upper Receiver with M-LOK Handguard - AT3 Tactical

Radical Firearms 16″ .300 Blackout Complete Assembled AR-15 Upper Receiver with M-LOK Handguard

Aero Precision M4E1-T AR-15 Assembled Upper 300 BLK 8″ – No BCG/Charging Handle

2 options

STNGR 10.5 Inch 300BLK Complete Upper w/ 13.5 Inch HWKXL® Handguard, BCG & CH

STNGR 10.5 Inch 300BLK Complete Upper w/ 13.5 Inch HWKXL® Handguard, BCG & CH

3 options