SHIPPING SAME DAY OR NEXT BUSINESS DAY

phone: 888-310-0284

AR Lower Parts

  • Gun Nuts® Pro Line Lower Parts Kit Gun Nuts® Pro Line Lower Parts Kit Gun Nuts® Pro Line Lower Parts Kit Gun Nuts® Pro Line Lower Parts Kit

    Gun Nuts® Pro Line Lower Parts Kit

    Precision-machined components with mil-spec fitment. The Pro Line Lower Parts Kit from Gun Nuts features OEM-spec components, proudly made in America with precision machining to guarantee reliable cycling with a perfect trigger pull and hammer reset...

    $72.99
  • Gun Nuts® Sporter Fire Control Group Gun Nuts® Sporter Fire Control Group Gun Nuts® Sporter Fire Control Group Gun Nuts® Sporter Fire Control Group

    Gun Nuts® Sporter Fire Control Group

    Includes a notched hammer for unshrounded BCGs. The Sporter Fire Control Group from Gun Nuts provides a modern, mil-spec reproduction of the old Colt and Bushmaster "notched" hammers, to ensure reliable cycling with unshrounded bolt carrier groups. All...

    $40.99
  • Sale
    MIAD Mission Adaptable Grip by Magpul MIAD Mission Adaptable Grip by Magpul

    Magpul® Adaptable Grip - MIAD Mission

    Got a preference for the way you think your AR grip should feel? Sure, anything but the original mil-spec grip, right? We hear ya. Fortunately for you, Magpul heard ya too. That's why there's the MIAD, the Mission Adaptable grip for your AR. It's just as...

    Was: $34.15
    Now: $22.97
  • M5 .308 Standard Lower Parts Kit by Aero Precision

    M5 .308 Standard Lower Parts Kit by Aero Precision

    If you plan to start an LR-308 build, you're gonna need a good lower parts kit. Aero Precision makes a lower parts kit designed for their M5, which is their own proprietarily designed .308 rifle that can also work with your LR-308 build, provided yours...

    $74.99

Finish or upgrade your stripped lower or fabricated 80% lower.

Finished your 80% lower? Grabbed a stripped receiver that you're ready to assemble? We've got you covered with all the AR lower assembly components you need -- or want to upgrade! Check out the mil-spec LPKs we have in stock. They work with all fabricated 80% units and every mil-spec "retail" lower on the market, including the various calibers you might own: 9mm, 5.56, .223, .308, 300 BLK and more.

Quality AR-15 Lower Parts, Triggers, and Kits

The stock AR trigger gets the job done, sure. But you can enjoy better shot placement and a more ergonomic grip with a few easy drop-in upgrades. We've partnered with Rise Armament, JMT, PSA, Hogue, and other top AR parts makers to offer up some of the best upgraded AR triggers and grips available for the AR platform. 

"How do I install my lower parts kit?"

Installing the lower parts kit in your stripped receiver or fabricated 80% lower is relatively easy. Some basic tools are required, which include:

Need help? Here's our detailed lower parts kit install guide!

"What parts do I need to finish my stripped lower?"

You'll need the following parts, which can all be found right on this page or by clicking the links below to filter products by type: 

Not sure what to buy? Here's our complete parts guide to building the AR-15.


DISCLAIMER: If you are new to the world of DIY gun building, you likely have a lot of questions and rightfully so. It’s an area that has a lot of questions that, without the correct answers, could have some serious implications. At GunBuilders.com, we are by no means providing this content on our website to serve as legal advice or legal counsel. We encourage each and every builder to perform their own research around their respective State laws as well as educating themselves on the Federal laws. When performing your own research, please be sure that you are getting your information from a reliable source.

We are a national retailer of individual components and not all products depicted on this website are legal in every state. Shipping of various products found on this website are prohibited to some states (such as California, Connecticut, District of Columbia, Hawaii, New Jersey, New York, Rhode Island, and Washington). The information, pictures, text or products presented on this website are not a representation by us, and should not be understood by you, that any product or completed firearm is legal to assemble or own in your state of residence. We encourage each and every builder to perform their own research about the state and federal laws that apply to them. It is your responsibility to understand the law and we encourage you to consult with an attorney or your local ATF representative.