5.56x45mm NATO Upper Receivers

AR-STONER AR-15 Sporter Billet Upper Receiver Stripped with 7" M-LOK Handguard Aluminum Black

AR-STONER AR-15 Enhanced Build Kit with Upper Receiver Assembly 5.56x45mm NATO 18" Barrel12" M-LOK Handguard, Complete Lower Parts Kit with Magpul MOE Furniture Black

STAG ARMS Stag15 AR15 Tactical Upper w/ 5.56 NATO 10.5" Nitride Barrel - M-LOK - Black

AERO PRECISION M4E1 Threaded Complete 7.5" 5.56 Upper Receiver

ROCK RIVER ARMS Comp UPPR Coyote 20"

NOVESKE Chainsaw 5.56 NATO 12.5" 30rd - Black

ANDERSON M4 7.5" Upper 5.56 1-in-9 Twist

AMERICAN TACTICAL IMPORTS Complete Upper 5.56 16" 1:8 BBL 10" M-LOK BLEM

LMT LM8 MRP Rifle Length Slick Upper Receiver

LMT CQB MRP Rifle Length Upper Receiver

KNIGHTS ARMAMENT SR-15 Upper Rcvr Assembled Notched for AR-15

GUNTEC AR-15 5.56 Complete Ultralt Pistol Kit (No Lower)

CHIAPPA FIREARMS M-Four Gen II Pro Upper 11.8" 10rd - FACTORY BLEM

CHIAPPA FIREARMS M-Four Gen II Pro Upper 11.8" 10rd

CHIAPPA FIREARMS M-Four Gen II Pro Upper 11.8" Blem/Refurbished

CHIAPPA FIREARMS M-Four Gen II Pro Upper 11.8" 28rd

Complete AR15 Upper- Bravo Mount, 5.56, 13.9" Pin/Weld (16" OAL)

Complete AR15 Upper Receiver - 5.56 - 12.5" Barrel Carbine - 9.8" MLOK - 4" Pin and Weld Extended Flash Hider

KAK Complete AR15 Upper Receiver - 5.56 NATO - 13.9" Barrel - 13" MLOK, 4 Prong FH, Pin and Weld

Colt's Manufacturing Upper, 223REM/556NATO, Black Finish, Dust Cover, Forward Assist, M4 Feed Ramps SP63528

Lead & Steel Llc JAG18URGODG Just As Good 5.56mm 18, Upper Receiver

Lead & Steel Llc JAG18URGGRY Just As Good 5.56mm 18, Upper Receiver

Lead & Steel Llc JAG18URGFDE Just As Good 5.56mm 18, Upper Receiver

Lead & Steel Llc JAG16URGODG Just As Good Upper Receiver 5.56mm 16