Colt 16 inch Monolithic Upper Receiver Assembly

$1,100.00 $950.00
(You save $250.00 )
(11 reviews)
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Colt LE6940 16 inch Monolithic Upper Receiver Assembly


The Colt LE6940CK Monolithic Upper Receiver Assembly feature's Colt's new monolithic upper receiver. In addition to an uninterrupted full-length front rail, this upper receiver allows for a free-floated barrel. This LE6940CK Monolithic Upper Assembly also features a gas-block mounted front flip-up sight with bayonet lug and a flip-up Magpul MBUS Polymer rear sight. The barrel is Colt's standard 16.1" chrome lined M4 barrel with an A2 flash hider up front.


Package Contents

  • Colt LE6940CK Monolithic Complete Upper Assembly
  • Complete M4 Full Auto Bolt Carrier Assembly
  • Charging Handle
  • Folding Front & Magpul MBUS Polymer Rear Sights
  • Manual


  • 16 Inch 1/7 twist Mil-Spec chrome lined MP tested barrel
  • Unique direct gas operating system eliminates the conventional operating rod and results in fewer and lighter components
  • Accommodates the full range of 5.56mm ammunition, including the NATO M855/SS109 and U.S. M193, utilizing a rifling twist of 1 turn in 7"
  • Straight-line construction disperses recoil straight back to the shoulder, increasing handling capabilities, especially during repeated fire
  • Cartridge case deflector allows easy operation in both right and left handed shooting positions for increased tactical applications
  • Muzzle compensator further reduces muzzle climb and helps eliminate flash and dust signatures
  • Ejection port cover protects the chamber from dust and mud
  • Field strips easily without special tools for simple field user maintenance
  • Flat top receiver allows for removable carrying handle and easy mounting of accessories
  • High strength materials for greater comfort and effectiveness
  • Caliber - 5.56mm
  • Gas Direct system, Locking bolt
  • Front Sight - Adjustable front
  • Magpul MBUS Polymer Rear Sight
  • Flash Hider


  • 5
    Colt 6940

    Posted by Erik on 25th Nov 2022

    This upper shoots great. I’ve had issues with some big ar names and poor qc/accuracy. Colt actually qc’s their products and it shows with the way that this 6940 shoots. Just buy it and be confident that colt knows what they are doing when it comes to the ar15.

  • 5
    Great Product!

    Posted by Arnis Plyavinsh on 11th Jul 2018

  • 5
    Colt LE6940 16 inch Monolithic Upper Receiver Asse

    Posted by J.S. on 6th Jul 2018

    All I can say is "OUTSTANDING" customer service. Please read descriptions very carefully. I made a mistake and they worked with me to resolve all issues. I highly recommend the Colt Receiver and Arms Unlimited! Thank you!

  • 5
    Colt LE6940 16 inch Monolithic Upper Receiver Asse

    Posted by Edward L. King on 18th Jun 2018

    Great deal on Colt product. Extremely fast shipping. 5 stars.

  • 5
    My LE901 Companion

    Posted by Volsracer on 15th Jun 2018

    So, the LE901 has always been my favorite .308 rifle. With its monolithic upper, it is one of Colt’s best offerings. But, since it was made to be adaptable to support .556 uppers, I have always wanted to pair up the upper from an LE6940. However, the price just seemed too high. Now AU offers the 6940CK at $750 and I just couldn’t refuse the deal. Not only that, but it came with the Troy sights that match the .308 upper. Great monolithic 556 upper by Colt, great combination with the LE901, and perfect deal from AU. Thanks!

  • 5
    Brand New Colt Rifle

    Posted by Robert Wirth on 31st May 2018

    Excellent Rifle, Very good price and quick shjipping

  • 5
    Colt LE6940 Upper

    Posted by Ted Kolodziej on 30th May 2018

    Extremely happy and can't believe the price. I logged into their e-mail up-dates and don't hesitate to buy from Arms Unlimited.

  • 5
    Another AU great purchase!

    Posted by Vlad on 28th May 2018

    Colt 6940 upper group good to go from AU. Just wish you guys were still in Torrance!

  • 5
    LE6940 Upper

    Posted by bernard on 22nd May 2018

    What a nice upper this. If you're on the fence jump on it. Patented one piece upper receiver/handguard design and it is made by Colt. What a good looking upper and I was pleasantly surprised of the slim feature of the handguard. When AU put it on sale I immediatley jumped on it. Mated perfectly to my Colt LE6920 lower and should fit with any mil-spec lower. You won't be disappointed.