5.56x45mm NATO Receivers

Geissele AR-15 Super Duty MOD1 Complete Upper Receiver 5.56x45mm with Pinned 14.5" Cold Hammer Forged Barrel M-LOK DDC

Spike's Tactical Spider AR-15 Stripped Receiver Set Anodized Flat Dark Earth

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

Geissele Super Duty AR-15 Barreled Receiver 5.56x45mm NATO 16" Barrel Black

Geissele Super Duty AR-15 Pistol Barreled Receiver 5.56x45mm NATO 11.5" Barrel Desert Dirt

Aero Precision M4E1 Stripped Lower Black

Aero Precision M4E1 Standard Assembled AR-15 Upper Receiver Aluminum Black

Aero Precision AR15 Stripped Upper Black

Geissele AR-15 Super Duty MOD1 Pinned and Welded Complete Upper Receiver 5.56x45mm 13.9" Cold Hammer Forged Barrel M-LOK DDC

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

Geissele Automatics Super Duty Stripped Upper Flat Dark Earth 5.56 16 Barrel

SilencerCo SCO-15 AR-15 Stripped Lower Receiver Anodized Black

LMT Defense MARS-L SOPMOD Complete Lower 5.56 / .300 AAC Blackout

Wilson Combat Forged Upper & Lower Set Multi-Caliber

One Horse AR-15 Stripped Lower Receiver Matte Black

Aero Precision M4E1 Stripped Lower Receiver Flat Dark Earth 5.56 / .223 Rem

LMT Defense MARS-L Stripped Lower 5.56 / .300 AAC Blackout

BCM MK2 RMS-M1T0 Mod-0 AR-15 Complete Lower Receiver Anodized Black

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

Colt Firearms LE6920CK-NHG Upper Kit Black 5.56NATO/.223Rem 16-inch

Aero Precision AR-15 M4E1-E Barreled Upper Receiver 5.56x45mm NATO 14.5" Barrel 12.7" ATLAS R-ONE Handguard Black

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

Faxon FF-15 X-TRA Lite AR-15 Stripped Receiver Set Titanium Cerakote

AERO PRECISION AR15 Complete Upper 16" 5.56 M4