5.56x45mm NATO Upper Receivers

Complete AR15 Upper Receiver - 5.56 - 12.5" Barrel Carbine Gas - 13" MLOK - 4" Pinned Flash Hider

Complete AR15 Upper Receiver - 5.56 - 16" Barrel Mid Gas - 15" MLOK

Geissele autos Super Duty AR-15 Receiver Set, Semi-auto, Lower/Upper Set, 223 Remington/556NATO, Anodized Finish, Olive Drab Green 05-1171ODG

WMD Guns Upper/Lower Receiver Set NIBXMSF15-3PC, Semi-automatic, 223 Rem/556NATO, Free Float Hand Guard, Nib-X Finish NIBXMSF15-3PC

Spikes Tactical Snowflake Lower/Upper Receiver Set, Semi-automatic, 223 Remington/556NATO, Cerakote Finish, Burnt Bronze, Includes 12 in SAR3 Rail STS1630-PT2S

Spikes Tactical Punisher Lower/Upper Receiver Set, Semi-automatic, 223 Remington/556NATO, Cerakote Finish, Patriot Brown, Includes 9 in SAR3 Rail STS1615-PB9S

Spikes Tactical Punisher Lower/Upper Receiver Set, Semi-automatic, 223 Remington/556NATO, Cerakote Finish, Barrett Brown, Includes 13.2 in SAR3 Rail STS1615-PN3S

Spikes Tactical Gadsden Lower/Upper Receiver Set, Semi-automatic, 223 Remington/556NATO, Cerakote Finish, Magpul FDE, Includes 9 in SAR3 Rail STS1634-PM9S

Spikes Tactical Gadsden Lower/Upper Receiver Set, Semi-automatic, 223 Remington/556NATO, Cerakote Finish, Flat Dark Earth, Includes 9 in SAR3 Rail STS1634-PFD9

Spikes Tactical Gadsden Lower/Upper Receiver Set, Semi-automatic, 223 Remington/556NATO, Cerakote Finish, Coyote Tan, Includes 13.2 in SAR3 Rail STS1634-PC3S

Spikes Tactical Crusader Forged Lower/Upper Receiver Set, Semi-automatic, 223 Remington/556NATO, Cerakote Finish, Combat Grey, Includes 7 in MLOK Rail STS1622-PG7M

Spikes Tactical Calico Jack Lower/Upper Receiver Set, Semi-automatic, 223 Remington/556NATO, Cerakote Finish, Magpul Foliage Green, Includes 7 in MLOK Rail STS1616-PF7M

DIAMONDBACK DB15 Combo 223 Remington/556NATO 16in 30rd Black Semi-Auto Rifle With Additional 300 Blackout Upper Receiver (DB1721K001)

NBS 14.5" (16" Overall) Mid-Length 5.56 NATO 1:7 Complete Upper w/ FSB and Pinned VG6 Precision Epsilon Muzzle Brake

JP Enterprises JP-15 Forged AR-15 Receiver Set

Centurion Arms CM4 5.56 Forged AR-15 Receiver Set

Lantac SF15 Forged Receiver Set

Aero Precision M4E1 Builder Set w/ 15" ATLAS R-ONE M-LOK Handguard - Chocolate Chip Camo

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

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

Aero Precision M4E1 Builder Set w/ 9.3" Enhanced M-LOK Handguard - Chocolate Chip Camo

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

Aero Precision M4E1 Builder Set w/ Enhanced M-LOK Handguard - OD Snakeskin - 10.7"

NBS 11.5" Slick Side 5.56 Nitride-Carbine M-LOK Upper Assembly