Advanced Armament Corp (AAC) Complete Upper. 16" .300 Blackout

Designed with precision, versatility, and suppressed performance in mind, the AAC Complete Upper in .300 AAC Blackout delivers exceptional reliability and accuracy in a compact, mission-ready package. Built by the pioneers of the .300 BLK platform, this upper receiver assembly is optimized for both subsonic and supersonic loads, making it ideal for suppressed shooting, home defense, or tactical operations.

At the heart of the upper is a cold hammer-forged barrel, engineered for durability and accuracy. The barrel length—typically available in 16” configurations—features a 1:7 twist rate, perfect for stabilizing heavier subsonic rounds. The pistol-length gas system ensures reliable cycling, especially when running suppressed.

AAC includes their signature suppressor-ready flash hider or muzzle brake, offering seamless compatibility with AAC silencers such as the SDN-6 or 762-SDN. The free-floating handguard offers full M-LOK compatibility for mounting mission-critical accessories, while the 7075-T6 forged upper receiver ensures strength without added weight.

Features:

• Caliber: .300 AAC Blackout (7.62x35mm)

• Barrel: 16” cold hammer-forged, 1:7 twist

• Gas System: Pistol-length (optimized for subsonic/suppressed fire)

• Muzzle Device: AAC 51T or flash hider (suppressor-ready)

• Handguard: Free-floating M-LOK compatible rail system

• Upper Receiver: Forged 7075-T6 aluminum, MIL-SPEC hardcoat anodized

• Charging Handle and BCG included

• 100% compatible with standard AR-15 lowers

Whether you’re building a precision suppressed platform or a lightweight CQB rifle, AAC’s Complete Upper in .300 Blackout delivers battle-proven performance in a purpose-built package.