LUTH-AR Rifle Kit Bull 20in with Fixed Stock (RKB-201)

LUTH-AR Complete 16in Lightweight AR Rifle Kit with Adjustable Stock (RKL-163)

NOVESKE Noveske9 Gen 4 Matched Upper & Lower Receiver Set (4000865)

SPIKE'S 5.56mm 16in Chrome Lined 1:7 Twist Flat Top Upper (STU5025-M4S)

SPIKE'S TACTICAL Midlength Complete 5.56x45mm NATO LE 16in AR-15 Upper Receiver With 12in CRR QUAD Rail (STU5035-CQ2F)

LUTH-AR A1 Upper Receiver 223/5.56mm Aluminum Black Hardcoat Anodize Receiver (UR-01-E3-SA)

SPIKE'S M4 LE 5.56mm 16in 1:7 Twist Flat Top Upper with Quad Rail (STU5025-R9S)

Spike's Tactical 223 Rem/556NATO 14.5" Mid-length Gas System 12" CRR Quad Rail Complete Upper Receiver (STU5050-CQ2D)