Aero Precision M4E1 Threaded .300 Blackout Complete Upper Receiver, 8In, 1-7 Twist, 5/8X24 Thread, ATLAS R-ONE Handguard, FDE Cerakote, APAR700711M1

Aero Precision M5E1 .308 Enhanced Upper Receiver,Cerakote,Flat Dark Earth, APAR308506AC

Aero Precision Complete Upper Receiver, M4E1-T, RM-15, 5.56x45mm NATO, 16In, Government, Mid Length, 1 in 7, 1/2 X 28, 15In, A2 Flash Hider, Anodized, OD Green, APAR700178M7

Aero Precision AR15 XL Assembled Upper Receiver, FDE, APAR611320AC

Aero Precision M4E1 Threaded .300 Blackout Complete Upper Receiver, 10In, 1-7 Twist, 5/8X24 Thread, ATLAS R-ONE Handguard, Black Anodized, APAR700702M4

Aero Precision M4E1 Threaded 5.56mm Complete Upper Receiver, 20In, 1-7 Twist, A2 Flash Hider, ATLAS R-ONE Handguard, Black Anodized, APAR700705M48

Aero Precision AR15 Stripped Upper Receiver, Uncoated, APAR501600C

Aero Precision Complete Upper Receiver, M4E1-T, RM12.7, 5.56x45mm NATO, 13.9In, Government, Mid Length, 1 in 7, 1/2 X 28, 12.7In, A2 Flash Hider, Cerakote, FDE, APAR700714M99

Rock River Arms Completed Upper Receiver, Mid-Length A4 9mm Luger, 16 Inch Barrel, 1-10 Twist, 1/2-36 Thread, A2 Flash Hider, Black, 9MM0388B

Aero Precision Complete Upper Receiver, M4E1, .300 Blackout Barrel EM-12 HG, No BCG/Charging Handle, Gen 2, Anodized Black, 16In, APAR600231M14

Aero Precision Complete Upper Receiver, M4E1-T, 5.56x45mm NATO, 11.5In, Government, Carbine Length, 1 in 7, 1/2 X 28, 10.3In, A2 Flash Hider, Anodized, OD Green, APAR700396M29

Luth-AR A3 Complete Upper Receiver Assembled, 16In, Lightweight Barrel, 5.56Mm, 1-7 Twist, 1/2 X 28 Thread, A2 Flash Hider, W/ Key MOD Palm Handguard, Black, BA-L16-7

Battle Arms Development 5.56 Caliber Lightweight Upper Receiver, Gen2, Black, BAD556-LW-UR

AR57 ULT Upper Receiver Assembly, 5.7X28mm, 18In, 16in Barrel, 1/2X28 Thread, AR57-ULT16

Grid Defense Complete Upper Receiver, 5.56Mm, 16 Inch, Carbine Length, 4150 M4 Barrel, 1-7 Twist, 14 Inch M-LOK Rail, A2 Flash Hider, Flat Dark Earth, GD16E14GFR556FDE

CMMG Mk4 5.56x45mm NATO Endeavor Upper Group Receiver, 18In, Coyote Tan, 55BFDAB-CT

CMMG Mk4 5.7x28mm Resolute Upper Group Receiver, 16.1In, Coyote Tan, 57B40E4-CT

Faxon Firearms .338 ARC ION 12.5in Complete Upper Receiver, Carbime Length, .750In, 1-8 Twist, 5/8X24 TPI, Black, Anodized Finish, FX338A5125-U

WMD Guns AR-15 A3/A4 Upper Receiver Forged, W/M4 Feed Ramps, Stripped, Nib-X, Battle Grey, 1-NIBXUF-Battle Grey

CMMG Mk4 5.7x28mm Resolute Upper Group Receiver, 16.1In, Charcoal Green, 57B40E4-CG

Battle Arms Development Workhorse 16in 5.56 Nato Upper Receiver, Assembly No Bcg No Ch, WH-UR-16-556

Brenton USA Upper Receiver, Tracker, .450 Bushmaster, 22in Barrel, 11/16X24 Thread, 1-24 Twist, Harvest Marblekote, Snow Marblekote, UPT22SM450

CMMG DISSENT Upper Receiver, Mk4, 300BLK, 10.5In, 1-7 Twist, 5/8X24 Thread, Zeroed Linear Compensator, Coyote Tan, 30BC239-CT

DEMO, Daniel Defense Upper Receiver With Flash Hider Assembly DD4 RIII URG, 5.56x45mm NATO, 25 Inch, 16 Inch Barrel, Government Profile, Mid-Length, 1-7 Twist, 1/2X28 Thread, M-LOK Handguard, Flash Suppressor, Salt Bath Nitride, FDE, 23-191-20088-011

CMMG DISSENT Upper Receiver, Mk4, 300BLK, 10.5In, 1-7 Twist, 5/8X24 Thread, Zeroed Linear Compensator, Tungsten, 30BC239-TNG