Colt's Manufacturing Upper, 223REM/556NATO, Black Finish, Dust Cover, Forward Assist, M4 Feed Ramps SP63528

AERO PRECISION M4E1 Threaded Complete Upper 16" 5.56 Barrel w/ 15" M-LOK ATLAS R-ONE Handguard - BLK

AERO PRECISION M5 .308 Stripped Upper Receiver - Anodized Black

AERO PRECISION AR15 5.56 NATO / 223 Rem 20" Complete Upper Receiver w/ Carry Handle | Black

Radian Weapons R0027 Complete Upper 300 Blackout 9" Black Barrel, 7075-T6 Aluminum Radian Black Receiver, Extended with Magpul M-LOK Handguard for AR-15

BUSHMASTER M4 Type Patrolman Flat Top A4 Upper 5.56 16" Black

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

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