Blackout Defense .223 Wylde 11.5 Barrel Carbine Length Fixed Gas Block Slick Side Upper Receiver

Wraithworks Billet Slick Side AR-15 Upper Receiver - Black | No Forward Assist or Brass Deflector

GUNTEC AR15 SLABSIDE STRIPPED BILLET UPPER RECEIVER BLACK

LEAD & STEEL All-Rounder Carbine Upper Receiver 5.56 14.5" FDE

BEAR CREEK ARSENAL 5.56 NATO COMPLETE UPPER 10. BRL 1:7 TWIST CARBINE LENGTH GAS MLOK

AERO PRECISION M4E1-T 5.56 NATO 11.5" Complete Upper Receiver | Black

BEAR CREEK ARSENAL 300 B/O COMPLETE UPPER 7.5 BRL 1:7 TWIST PISTOL LENGTH GAS MLOK

BALLISTIC ADVANTAGE Low Profile Gas Block .936" Fits AR15