JE Machine Tech

JE4 AR-15 Lower Build Kit

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JE4 AR 15 Lower Build Kit

The JE4 AR 15 Lower Build Kit from Black Rifle Depot is the perfect solution for the lightweight and high-quality lower build. This kit includes a skeletonized Mil-spec stock, made in America, for a sleek and light look. The complete Mil-spec lower parts kit, also made in America, provides all the components you need to finish your lower build. The Mil-spec buffer tube kit, made in America, includes a 6-position aluminum receiver extension, 3 oz buffer, castle nut, end plate, and carbine spring. This kit is designed to meet the highest quality and performance standards and is backed by a limited lifetime warranty. Upgrade your AR 15 build with the JE4 AR 15 Lower Build Kit from Black Rifle Depot.


  • Includes Skeletonized Mil spec Stock
  • Includes Complete Mil Spec Lower Parts Kit
  • Includes Mil Spec Buffer Tube Kit 
    • 6-position 6061-T6 Aluminum Receiver Extension
    • 3 oz Buffer
    • Castle Nut & End Plate
    • Carbine Spring
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Warranty Information

This kit comes with our LIMITED LIFETIME WARRANTY* in the rare case you need one. Each part is personally inspected for quality and hand packaged to ensure your satisfaction. *Note: Warranty only valid when used with mil-spec lower, warranty does not cover use with 80% lower.
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102 Reviews

  • 4
    Parts kit

    Posted by James on Nov 27th 2023

    Very nice kit. All tolerances were tight and clean fitment. Only issue was butt stock. It was a very loose fit and uncomfortable. Overall pleased with quality for price. Thank you. I will replace butt stock with hogue.

  • 4
    Good parts kit

    Posted by Adam Pettigrew on Nov 10th 2023

    Everything was great except the je4 stock. It is very loose on the buffer tube. I will have to find something to tighten it up. I have ordered from BRD many times and I will be back.

  • 5

    Posted by Terry Einspahr on Apr 19th 2023

    Thank you so much for a great product!! The only issue I had was the trigger guard. I don't have an allen wrench that small. So it got put on the back burner till I get one!! The rest of the build was pretty easy and painless!! Thank you again.

  • 5

    Posted by Kyle on Dec 21st 2022

    Everything you need to finish your stripped lower. Wish it came with a few more springs because we all know what happens sometimes, but it is a great lower

  • 4
    Lower parts kit

    Posted by Larry Gullett on Dec 21st 2021

    Works just fine

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Explore Black Rifle Depot's impressive selection of AR15 parts and AR15 parts kits, all available at discounted prices. Whether you want to enhance your current setup or embark on a new build, they offer a wide range of high-quality components to meet your needs. With their affordable prices, you can upgrade your AR15 without stretching your budget. Step into the world of Black Rifle Depot and discover how you can elevate your AR15 experience.