Colt 10.5 inch 9mm SMG Upper Receiver Assembly

(13 reviews)
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Colt LE6991 10.5 inch 9mm SMG Upper Receiver Assembly


The Colt LE6991CK Upper Assembly is utilized on the R0911 SMG model submachine gun. This upper receiver allows for a free-floated barrel and also features a gas-block mounted fixed front sight post with bayonet lug. The barrel is Colt's standard 10.5" chrome lined M4 barrel with an A2 flash hider up front.

Package Contents

  • Colt LE6991CK Complete Upper Assembly
  • Complete 9mm SMG Full Auto Bolt Carrier Assembly
  • Charging Handle


  • 10.5-Inch 1/10 RH 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 9mm NATO ammunition
  • 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 - 9mm
  • Closed Bolt, Blowback
  • Front Sight - Adjustable front
  • Flash Hider


  • 5
    Colt upper

    Posted by Richard Knipe on 7th Jun 2018

    good service, nice product.

  • 5

    Posted by EDWARD FULLMER on 19th Mar 2018


  • 5
    Great price, fast shipping!

    Posted by Brian on 28th Feb 2018

    I ordered a Colt LE6991 10.5 inch 9mm SMG upper receiver assembly for my pistol build from ArmsUnlimited. Product was brand new and as described. Shipping was super fast. Box was also wrapped in a plastic which was a bonus because the day it was delivered it was pouring rain. Will order from them again. Thanks AU.

  • 5
    Great price

    Posted by TvsFrank on 20th Nov 2017

    Just wish it was in a factory box.

  • 5
    Good to Go!!!!

    Posted by John D on 29th Sep 2017

    The upper came farm fresh still in the wrapper. 9mm upper is well built, chrome lined, and double heat shields. If you want to build a 9mm Para SBR or Pistol this is the set up to get. Don't be fooled by cheaper stuff by other makers that don' t have the correct upper receiver without gas deflector and no short dust cover or ramped BCG. Not sure why we need a bayonet lug, but its there and super cool to top it off.

  • 5
    High Quality, Genuine Colt

    Posted by Unknown on 7th Sep 2017

    Mil spec chrome lined barrel with latest revision bolt carrier which is ramped to accept the std 5.56 hammer. They also used the double insulated hand guards but lack the pop up dual aperture rear sight depicted in the photo. I would recommend this and the CMMG MK 9 dedicated lower to anyone looking to build a 9mm AR15.

  • 4
    Colt LE6991CK

    Posted by Kirk Fleming on 28th Aug 2017

    Only wish you would have shipped this upper receiver kit in the original Colt packaging/box. Believe you took it out so it would fit in a smaller standardized USPS Priority tube (triangular box).

  • 5
    Colt LE6991 10.5 inch SMG Upper Receiver Assembly

    Posted by Robert Arndt on 4th Jul 2017

    Fit and Function and Accuracy all combined in this small little upper

  • 5
    Colt upper

    Posted by JD on 19th May 2017

    Excellent...exactly as described.