5.56x45mm NATO SBR Barrels & Upper Receivers

Daniel Defense MK18 AR-15 Pistol Complete Upper Receiver 5.56mm NATO 10.3" Barrel Flat Dark Earth

Daniel Defense MK18 AR-15 Pistol Complete Upper Receiver 5.56mm NATO 10.3" Barrel Black

Daniel Defense DDM4v7 S AR-15 Complete Upper Receiver 5.56x45mm NATO 11.5" Barrel

Rosco Manufacturing Bloodline AR-15 Barrel 5.56x45mm NATO 11.5" M4 Contour 1:7" Twist Black Nitride

HK MR556 A4 AR-15 Complete Upper Receiver 5.56x45mm NATO 11" Barrel

Geissele AR-15 Super Duty MOD1 Complete Upper Receiver 5.56x45mm 11.5" Cold Hammer Forged Barrel M-LOK Black

Battle Arms Workhorse AR-15 Pistol Barreled Upper Receiver 5.56x45mm NATO 9.5" Barrel

LBE Unlimited Ready Build Kit Complete Upper 5.56 / .223 Rem 14.5 Threaded Barrel Mid Length Handguard

LBE Unlimited AR-15 Ready Build Kit Complete Upper 5.56 13.7 Barrel

Noveske Crusader AR-15 Barrel 5.56x45mm NATO 12.5" 1:7" Twist Stainless with Low Profile Gas Block and Gas Tube

Noveske Infidel AR-15 Barrel 5.56x45mm NATO 13.7" Medium Contour 1:7" Twist Bead Blasted Stainless with Low Profile Gas Block

Midwest Industries AR-15 Pistol Barreled Upper Receiver 5.56x45mm NATO 10.5" Barrel

LBE Unlimited AR-15 Ready Build Kit Complete Upper 5.56 / .223 Rem 7.5 Barrel

Colt AR-15 Pistol Complete Upper Receiver 5.56x45mm NATO 14.5" Barrel

Geissele USASOC URG-I Near Clone AR-15 Pistol Complete Upper Receiver Improved Complete 5.56x45mm NATO 10.3" Barrel with Surefire SF4P

Geissele AR-15 Super Duty MOD1 Complete Upper Receiver 5.56x45mm 11.5" Cold Hammer Forged Barrel M-LOK DDC

LBE Unlimited Ready Build Kit Complete Upper 5.56 / .223 Rem 12.5 Barrel Mid Length Gas Handguard

Daniel Defense GL/SSC URG AR-15 Complete Upper Receiver 5.56x45mm NATO 12.5" Barrel

Geissele Automatics Super Duty MOD1 5.56 12.5 Barrel w/ HuxWrx Flash Hider

Maxim Defense PDX AR-15 Complete Upper Receiver 5.56x45mm 5.5" Barrel Black

Maxim Defense PDX AR-15 Complete Upper Receiver 5.56x45mm 5.5" Barrel Arid

Ballistic Advantage Performance Series Barrel Black 5.56 11.3 Carbine

Geissele AR-15 Super Duty MOD1 Complete Upper Receiver 5.56x45mm 12.5" Cold Hammer Forged Barrel M-LOK DDC

Geissele CHF AR-15 Barrel 5.56x45mm NATO 14.5" Heavy Contour 1:7" Twist