Luth-AR A1 / C7 Stripped AR-15 Upper Receiver - M4 Feed Ramps

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

LUTH-AR A1 Stripped Upper Receiver 223/5.56mm Aluminum Black Hardcoat Anodize Receiver For M16 (UR-01-M16)

GUNTEC AR15 SLABSIDE STRIPPED BILLET UPPER RECEIVER BLACK

AERO PRECISION M5 .308 Stripped Upper Receiver - Anodized Black

AERO PRECISION M5 Stripped Upper Receiver FDE

Battle Arms Development WH556-URS-ODG Workhorse Upper Receiver Aluminum OD Green Anodized Receiver for AR15/M4

LBE Unlimited M4 Stripped Upper Receiver, Fits AR15, Black Finish ARSTUP