Complete 300 AAC BLACKOUT Upper Receiver Assembly
- 12.5" Nitrided 1:7" Twist Barrel, threaded 5/8-24
- AAC 51T BLACKOUT™ Flash Hider
- "Full Auto" BCG
- KAC URX Rail
- Ready to drop onto your AR15/M16/M4 lower! Works with an AR lower with "Mil-Spec" push pin locations.
-The 9" and 12.5" AAC 300BLK Uppers are designed for use with a carbine receiver extension, standard GI Buffer Spring, and an H2 Buffer.
-The 16" AAC 300BLK Upper is designed for use with a carbine receiver extension, standard GI Buffer Spring, and a CARBINE Buffer.