Colt AR15/M4 Carbine Upper Receiver Assembly

$179.99 $150.00
(9 reviews)
Current Stock:

Factory Colt upper receiver assembly to build your AR15, M16 or M4. Compatible with all mil-spec AR15/M4/M16 lower receivers. Includes forward assist assembly, and ejection port cover. Manufactured to truly meet and exceed all Mil Spec standards.


  • 5
    Fast shipping Great price

    Posted by Jason Harada on 3rd May 2022

    Been waiting for these to come back in stock. Great price and shipped right away.

  • 5
    Fast secure shopping experience

    Posted by David Doc Burns on 25th Mar 2022

    When looking for quality, professional grade firearms and components, Arms Unlimited is my go-to. When clients want the best AU ships quality goods quickly and security.

  • 4
    Decent Price; Poor Packing

    Posted by Christopher Cusano on 26th Jul 2020

    Item arrived with a ding as there was no extra packing around it to prevent damage in the soft envelope.

  • 5
    Colt Upper

    Posted by Martin Schiller on 23rd Jul 2020

    Usual Colt quality, and a decent price, considering the boys at the dancing pony can’t make up their minds whether they love civilians or not!

  • 3

    Posted by Bryan on 22nd Jul 2020

    CAGE number, dot marked, not C marked, as in photo. I even put in the comments, "Ensure C marked, as in photo". Poorly packaged. I'll use it, but I'm disappointed.

  • 4
    Posted Picture misleading no "C"

    Posted by Kristen Randall on 21st Jul 2020

    The picture showed a "C" forge code, the uppers that arrive had the cage code instead of the "C" The 4 uppers I purchased ship in a plastic bag each upper was in a plastic bag, not the best packing in my experience. I do like the deals from this company - these uppers are Colt & are new. Thanks Kristy

  • 3
    Colt M4 upper receiver

    Posted by Norm Reno on 21st Jul 2020

    Ordered and received my Colt M4 upper receiver. The item was brand new and in great condition. It will work nicely for my build. The only drawback was it was not stamped exactly as pictured in the ad. The pictured upper had the offset square and prominent "C" for Colt on the ejection port side of the receiver. The receiver I received, had the offset square and a cage code of "13629" stamped on the receiver, which is also a Colt marking. It is not a major issue, it is a Colt receiver and will work as intended, but I was hoping to get a "C" stamped receiver as listed in the Arms Unlimited ad.

  • 5
    Colt M4 Upper Receiver

    Posted by Ryan Cooper on 20th Jul 2020

    Excellent Upper and Would Definitely Recommend this if yours looking for a Top Tier Milspec Upper Receiver For your Clone Build. Cage Code Square Forge.

  • 3
    Not a keyhole upper as pictured.

    Posted by Tyler M on 20th Jul 2020

    Cosmetically and functionality are fine for the upper, but disappointing that the colt upper pictured (keyhole) is not the actual product and actually a cage code variant.