5.56x45mm NATO Upper Receivers

NBS Premium Series 16" Upper Assembly w/ BA Barrel and Geissele MK8 Handguard

NBS 10.5 5.56 Gov / SOCOM Carbine M-LOK Upper Assembly

NBS 20" 5.56 Rifle Quad Rail Upper Assembly

NBS 20" 5.56 Rifle M-LOK Upper Assembly

NBS 16" 5.56 Government Profile Quad Rail Complete Upper

NBS 16" 5.56 Left Handed Complete Upper

Centurion Arms CM4 Forged 5.56 Stripped Upper/Lower Set - Thermal Fit

Aero Precision M4E1 Threaded AR-15 Barreled Upper Receiver 5.56 Mid-Length - ATLAS S-ONE - 16"

Anderson Manufacturing AM-15 AR-15 Builder Set - 15" - Punisher

Aero Precision M4E1 Builder Set w/ 15" ATLAS S-ONE M-LOK Handguard - Rattlesnake Camo

Aero Precision M4E1 Builder Set w/ 12.7" ATLAS R-ONE M-LOK Handguard - Gunmetal Grain

Aero Precision M4E1 Builder Set w/ 15" ATLAS R-ONE M-LOK Handguard - Gunmetal Grain

Aero Precision M4E1 Builder Set w/ 15" ATLAS S-ONE M-LOK Handguard - Gunmetal Grain

Aero Precision M4E1 Builder Set w/ 15" Enhanced M-LOK Handguard - Gunmetal Grain

Aero Precision M4E1 Builder Set w/ 10.7" Enhanced M-LOK Handguard - Gunmetal Grain

Aero Precision M4E1 Builder Set w/ 9.3" ATLAS S-ONE M-LOK Handguard - Cavern Flecktarn Camo

Aero Precision M4E1 Builder Set w/ 9.3" ATLAS R-ONE M-LOK Handguard - MTC Dark Camo

Aero Precision M4E1 Builder Set w/ Enhanced M-LOK Handguard - OD Snakeskin - 15"

Aero Precision M4E1 Builder Set w/ 9.3" ATLAS S-ONE M-LOK Handguard - Multi Terrain Camo

Aero Precision M4E1 Builder Set w/ 15" ATLAS R-ONE M-LOK Handguard - Midnight Rider Cerakote

Aero Precision M4E1 Builder Set w/ 9.3" ATLAS S-ONE M-LOK Handguard - Midnight Rider Cerakote

Aero Precision M4E1 Builder Set w/ 15" ATLAS R-ONE M-LOK Handguard - Yorktown Cerakote

Aero Precision M4E1 Builder Set w/ 9.3" ATLAS R-ONE M-LOK Handguard - Yorktown Cerakote

Aero Precision M4E1 Builder Set w/ 15" ATLAS S-ONE M-LOK Handguard - Yorktown Cerakote