Colt 10.3 inch Monolithic Upper Receiver Assembly

$1,200.00 $1,100.00
(22 reviews)
Current Stock:

Colt LE6945 10.3 inch Monolithic Upper Receiver Assembly


The Colt LE6945CK Monolithic Upper 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 LE6945CK Monolithic Upper Assembly also features a gas-block mounted front flip-up sight and a flip-up rear sight. The barrel is Colt's standard 10.3" chrome lined M4 barrel with an A2 flash hider up front.

Package Contents

  • Colt LE6945CK Monolithic Complete Upper Assembly
  • Complete M4 Full Auto Bolt Carrier Assembly
  • Charging Handle
  • Backup rear sight
  • Folding Front Sight
  • Manual


  • 10.3-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
  • Target style rear sight features dual apertures (0-200m, 300-600m) and adjusts for both windage and elevation
  • High strength materials for greater comfort and effectiveness
  • Caliber - 5.56mm
  • Gas Direct system, Locking bolt
  • Front Sight - Adjustable front
  • Rear Sight - Target sight adjustable for windage and elevation
  • Flash Hider


  • 5
    The absolute best upper

    Posted by Wyoming Wyoming on 23rd Aug 2022

    Have every length of colt upper on all select fire weapons and the Monolithic preforms by far the best! Colt uppers by far are superior to most if not all! Most do not last 10,000 rounds but all my colts running strong! Only 2,000 so far through Monolithic and not a single failure. Seems to run both cleaner and cooler? To be determined! Well worth the extra money!

  • 5
    Great Upper and great service!

    Posted by Bryce Wyble on 19th Dec 2020

    I love Colt’s LE69xx series of rifles, and this one was no exception. Arms Unlimited did their part in getting the upper to me on time, and at a good price!

  • 5
    Colt 10.3 inch Monolithic Upper Receiver Assembly

    Posted by James T on 8th Dec 2019

    Daniel and his staff provide hard to find new Colt products at great prices. Always a great experience!

  • 5
    Pony Up!

    Posted by Roger Herron on 27th Aug 2019

    These guys sell real Colt parts, which are NIB, and fresh from Colt. Downside, they don't seem to ever restock, and when they are out, they are out of stock.

  • 5

    Posted by Leo on 30th Sep 2018

    Excellent product and shipping.

  • 5
    Top Tier Quality

    Posted by Carl Mallett on 20th Jul 2018

    Wish I had gotten it sooner! Authentic Colt Monolithic Upper shipped in Colt logo box. Upper in pristine condition, highly recommend this upper, super accurate, runs easily with 5.56 suppressor

  • 5
    Colt LE6945 Monolithic Upper Receiver Assembly

    Posted by Richard Veres on 15th Jun 2018

    This is Colt's BEST offering!! I gave it 5 Stars simply because I couldn't give it 6!! The item arrived in pristine condition in Colt factory packaging. Arms Unlimited ROCKS. Thanks guys!!

  • 5
    Fantastic factory Colt

    Posted by Unknown on 12th Jun 2018

    Real deal Colt upper in factory retail cardboard box. Comes with accessory pack, two manuals. Magpul BUIS. Square forge mark. Excellence.

  • 5

    Posted by chainweight on 12th Apr 2018

    Beautiful product, packaged nice in Colt box, and delivered lightning fast. Will definitely buy from Arms Unlimited again!