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21 of 21 Items
  • Sale
    Mil-Spec AR15 Lower Parts Kit (w/ Hammer and Trigger)

    Mil-Spec AR15 Lower Parts Kit (w/ Hammer and Trigger)

    Want an AR-15 trigger that suffers no creep, take-up, or over-travel? Looking for the easiest-to-install LPK? How about the most affordable parts kit possible? The mil-spec AR-15 LPK comes in at a low-price with machining and performance that truly feels...

    Was: $46.79
    Now: $38.99
  • Premium AR-15 Lower Parts Kit Premium AR-15 Lower Parts Kit 2 Premium AR-15 Lower Parts Kit 3 Premium AR-15 Lower Parts Kit 4

    Premium AR-15 Lower Parts Kit

    A lower parts kit is essential to finishing your 80% lower. To have multiple build kits, or lower receivers to swap out on your AR-15 rifle, it’s crucial to have multiple lower parts kits. Sure there are no fancy color coded bags, but rest assured...

    $63.99
  • Sale
    KAK-308-LPK

    LR-308/AR-10 Lower Parts Kit (w/ Hammer and Trigger)

    We strive to provide the most accurate photographs of our product whenever possible. Due to availability limitations and supply chain constraints, slight variations of the trigger and hammer finsh (stainless or black) may occur.  Want an LR-308...

    Was: $76.79
    Now: $63.99
  • Sale
    KAK AR15 LPK - Missing Parts Kit

    AR15 LPK Missing Parts Kit

    This AR15 LPK Missing Parts Kit has all the essentials for any lost parts, replacement parts, or for your next custom build. All parts are proudly made in the USA. This LPK Missing Parts Kit comes with: (1) buffer retainer (1) buffer retainer spring (1)...

    Was: $11.99
    Now: $9.99
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    AR15 LPK - Basic Build Kit

    AR15 LPK - Basic Build Kit

    The Kak Industry AR15 Lower Parts Kit comes with all of the basic essentials you'll need for your own custom AR15 build. This build kit includes the following: bolt catch kit magazine catch kit hammer & trigger pins pivot pin & detent &...

    Was: $32.39
    Now: $26.99
  • Sale
    Magpul®  MOE® Enhanced AR15/M4 Polymer Trigger Guard Magpul®  MOE® Enhanced AR15/M4 Polymer Trigger Guard Magpul®  MOE® Enhanced AR15/M4 Polymer Trigger Guard

    Magpul® MOE® Enhanced AR15/M4 Polymer Trigger Guard

    Stop installing that mil-spec aluminum trigger guard on every AR you build. The Magpul® MOE® Enhanced AR15/M4 Polymer Trigger Guard is way better. Why? For starters, it's super ergonomic and gives your trigger finger much more room which is great...

    Was: $10.79
    Now: $8.99
  • Aero Precision AR15 Enhanced Lower Parts Kit

    Aero Precision AR15 Enhanced Lower Parts Kit

    For your next AR-15 build, you should start with a quality lower parts kit, so you don't have to replace it later. Aero Precision gives you their AR-15 Enhanced Lower Parts Kit to start your build off with. It's a quality kit, and also comes upgraded...

    $114.99
  • Aero Precision M5 .308 Standard Lower Parts Kit

    Aero Precision M5 .308 Standard Lower Parts Kit

    If you're starting an LR-308 build, you'll 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 is based...

    $99.99
  • Sale
    AR15 Pin & Detent Parts Kit

    AR15 Pin & Detent Parts Kit

    The KAK Industry AR15 Pin & Detent Parts Kit is made out of the best parts on the market. This kit is great for replacement parts, a new build, or having spare parts. This kit includes: a pivot pin takedown pin pivot and takedown detents hammer and...

    Was: $23.99
    Now: $19.99
  • Aero Precision M5 .308 Enhanced Lower Parts Kit

    Aero Precision M5 .308 Enhanced Lower Parts Kit

    If you're starting an LR-308 build, you'll need a good lower parts kit. It'd also be nice if your lower parts kit came with a grip that was more comfortable than the standard A2 grip. Aero Precision makes a lower parts kit designed for their M5, which is...

    $134.99
  • Sale
    WMD Guns NiB-X Lower Parts Kit, Mod 3

    WMD Guns NiB-X Lower Parts Kit, Mod 3

    Even minor changes to an AR's lower parts kit can make someone get more out of their shooting experience. This lower parts kit by WMD Guns is mil-spec save for one detail: the trigger, hammer, and disconnector have all been coated in nickel boron. Their...

    Was: $107.99
    Now: $89.99
  • Strike Industries Enhanced Lower Parts Kit

    Strike Industries Enhanced Lower Parts Kit

    If you've got a worn out or mil-spec lower parts kit in your AR-15 that needs replaced, or if you just want to refresh the controls on your rifle, you need to get the Strike Industries Enhanced Lower Parts Kit. It'll rejuvenate your lower assembly and...

    $104.99
  • Spike's Tactical Lower Parts Kit for .223/5.56

    Spike's Tactical Lower Parts Kit for .223/5.56

    The mil-spec lower parts kit is good enough. It does the job it's meant to do. The trigger, hammer, disconnector, detents, springs, and roll pins are perfectly suited to the job of making your lower (and the rest of your AR) work as intended. In keeping...

    $89.99
  • Spike's Tactical - AR-308 Lower Parts Kit

    Spike's Tactical - AR-308 Lower Parts Kit

    The Spike's Tactical AR-308 Lower Parts Kit sports military-grade hardware (minus that third safety position) with a great fit and finish. This parts kit is manufactured for Spike's Tactical's forged sets and may not be compatible with any other large...

    $79.99
21 of 21 Items

The lower parts kit (LPK) is one of the most important parts of any AR build. The LPK includes all the parts necessary to chamber a round, flip the safety, squeeze the trigger, and fire a round downrange using your AR-15 lower. A lower parts kit is absolutely necessary to convert your 80% lower receiver (or retail-purchased stripped lower) from a piece of aluminum or polymer to a fully-functioning firearm, quickly and cost-effectively.

Not sure which LPK you need for your AR? Read the parts kit compatibility guide!

Need help with assembly? 

 

The Lower Parts Kit: What's Included

All lower parts kits include the following components for assembling the lower receiver, ordered alphabetically:

  • Bolt Catch
  • Bolt Catch Plunger 
  • Bolt Catch Roll Pin
  • Bolt Catch Spring
  • Buffer Retainer
  • Buffer Retainer Spring
  • Disconnector
  • Disconnector Spring
  • Hammer
  • Hammer Pin
  • Hammer Spring
  • Magazine Catch
  • Magazine Catch Button
  • Magazine Catch Spring
  • Pistol Grip
  • Pistol Grip Lock Washer
  • Pistol Grip Screw
  • Pivot Pin
  • Pivot Pin Detent
  • Pivot Pin Detent Spring
  • Safety Selector Lever
  • Safety Lever Detent 
  • Safety Lever Detent Spring
  • Takedown Pin (Front/Rear)
  • Takedown Pin Detent 
  • Takedown Detent Springs
  • Trigger
  • Trigger Guard
  • Trigger Guard Roll Pin
  • Trigger Pin
  • Trigger Spring

 Additional Parts Required for Install

To complete the AR-15 lower parts kit install, you will also need a castle nut and latch plate. These two components are not usually included with the LPK but they are required for securing the safety lever detent and spring, and the buffer tube. They typically come with your tube or buttstock assembly instead. An LPK and buttstock combo kit is available.  If you already have a parts kit, simply grab the buttstock, tube, nut and plate here.

AR-10 and Pistol Parts Kits

We cater to all AR platforms, 80% builds, and calibers, so we've sourced quality parts kits for your pistol-caliber carbines and AR-9s, and your 1911, Glock-compatible, and Sig handgun builds. Want to throw more lead downrange with your black rifle? Grab a regular AR-15 LPK for your 6.5 Creedmoor or .308 AR-10 project. All 5.56/.223 parts kits are designed to work with both retail-purchased .308 stripped receivers and our LR-308 80% lower receivers. In fact, virtually all AR-type weapons use an AR-15 LPK!

Here's a detailed guide covering LPK compatibility.

Confused about completing your .308 build?

Converting to Drop-in Triggers

One of the easiest upgrades any AR owner can do is swap out that factory hammer and trigger for a drop-in trigger. These custom, self-contained fire control units include a new hammer, trigger, disconnector, and sear. They quite literally drop into the lower receiver once a factory parts kit has been installed. Just punch out the hammer and trigger pins, remove the trigger, hammer, disconnector, and springs, drop the new trigger assembly in, and replace the pins. It's incredibly easy and takes just a few minutes. Pick up a quality upgraded drop-in trigger here. It'll help tighten up your groupings and make for quicker follow-up shots.

 


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 80-lower.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.