5.56x45mm NATO Upper Receivers

Sons of Liberty Gun Works M4-EXO3 5.56mm 11.5" Bbl Car Gas EXO3 Rail A2FH Liberty Fighting Bbl & Mil-Spec Upper Receiver U-M4EXO3-556-115-A2

Sons of Liberty Gun Works M4-L89 5.56mm 12.5" Bbl Car Gas L89 Rail A2FH Liberty Fighting Bbl & Mil-Spec Upper Receiver U-M4L89-556-125-A2

SOLGW M4L89BSUPPER-14.5-CHF-556 UPPER 14.5 556

Sons of Liberty Gun Works SOLGW L89 5.56mm 12.5" No BCG/CH Upper Receiver M4L89UPPER-12.5-556

Heckler and Koch MR556A4 URK Complete Upper 5.56 / .223 Rem 14.5 Barrel SBR

Anderson Stripped Sport Upper Receiver - Black

LANTAC SF AR-15 Forged Builder Set Blk 15" Spada M-LOK

LANTAC SF AR-15 Forged Builder Set Blk 13.5" Spada M-LOK

BUSHMASTER QRC Upper 5.56 NATO 16" - Black

BUSHMASTER QRC Complete Upper 5.56x45 16" CMV Nitride

BUSHMASTER Bravo Zulu Upper 223 Rem/5.56 NATO 16" Black

Colt AR-15 Barreled Upper Receiver 5.56x45mm NATO 11.5" Barrel

Colt Firearms LE6933 Complete Upper 5.56 / .223 Rem 11.5 Threaded Barrel w/ Surefire SF3 Flash Hider

Colt Firearms LE6933 Enhanced Patrol Rifle II Complete Upper 5.56 11.5 Threaded Barrel w/ HUXWRX Flash Hider

Colt LE6921SOCOM 5.56mm 14.5" Heavy Bbl KAC Rail Matech BUIS Matte Black Upper Receiver Conversion Kit LE6921SOCOMCK

Colt M4 to M5 PDW 5.56 x 45mm 10.3" Heavy Bbl Matte Black Conversion Kit CM556-10H-CK

Colt M4 to M5 Carbine 5.56 x 45mm 14.5" Heavy Bbl Matte Black Conversion Kit CM556-14H-CK

Colt M4 to M5 Carbine 5.56 X 45mm 16.1" Bbl Matte Black Conversion Kit CM556-16-CK

PRI Mark 12 Mod 0 Gen II AR-15 Complete Upper Receiver 5.56x45mm NATO 18" Barrel 1:7" Twist Black

LMT MRP-L M-LOK 11.5" Shovelnose Monolithic Upper Receiver

Ar-15/M16 G4 Side Charging Upper Receiver - G4 Side Charging Upper Receiver

LWRC IC-A5 Flat Dark Earth 5.56mm 10.5-inch

HM Defense 95MBUP556 MonoBloc Upper 223 Rem, 5.56x45mm NATO 9.50" Black Cerakote Barrel, 7075-T6 Aluminum Black Anodized Receiver, 8.50" M-LOK Free-Float Handguard for AR-15 Pistol

HM Defense 125MBUP556 MonoBloc Upper 223 Rem, 5.56x45mm NATO 12.50" Black Cerakote Barrel, 7075-T6 Aluminum Black Anodized Receiver, 10.37" M-LOK Free-Float Handguard for AR-15 Pistol