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AR Lower Parts Kit

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

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

    This LPK offers the parts needed to finish your lower, and for a fraction of the cost of a "retail" bought assembly. This lower parts kit comes with all the internal parts needed to finish your lower, from the pivot pin to the trigger. With this kit...

    $39.99
  • AR15 LPK - Missing Parts Kit

    AR15 LPK - Missing Parts Kit

    The AR15 Missing Parts Kit is perfect for any lost parts, replacement parts, or for your next custom build. What's Included? Buffer retainer (1) Bolt catch spring (2) Bolt catch detent (1) Selector detent (2) Disconnector spring (2) Buffer retainer...

    $9.99
  • LR-308/AR-10 Lower Parts Kit (w/ Hammer and Trigger)

    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.  If you're looking...

    $54.99
  • AR15 LPK - Basic Build Kit

    AR15 LPK - Basic Build Kit

    This AR15 Basic Lower Parts Kit includes all of the basic necessities needed for your own custom build. Most importantly what comes with this kit are the following, a bolt catch kit, magazine catch kit, takedown pin & detent & spring, pivot pin...

    $26.99
  • 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 a key part to finishing your lower. It's one of the most important aspects of your AR-15 as far as quality is concerned. This lower parts kit offers all the parts needed to finish your stripped receiver. You'll also need an upper...

    $64.99
  • AR15 LPK Pin And Detent Kit by KAK

    AR15 LPK Pin And Detent Kit by KAK

    The KAK Industry AR15 Pin And Detent Lower Parts Kit was manufactured with top of the line materials for the best quality parts. This kit is great for replacement parts, a new build, or having spare parts. This kit comes with a pivot pin, takedown pin,...

    $19.99
  • AR-308 Lower Parts Kit - Spike's Tactical

    Spike's Tactical - AR-308 Lower Parts Kit

    The Spike's Tactical AR-308 Lower Parts Kit has a great fit and finish along with a military grade design that is built to last. This parts kit is meant to be used with Spike's Tactical's forged sets and may not be compatible with any other large frame...

    $64.80
  • Gun Nuts®  OH $#!+ Kit - Lower Parts Kit Gun Nuts®  OH $#!+ Kit - Lower Parts Kit Gun Nuts®  OH $#!+ Kit - Lower Parts Kit Gun Nuts®  OH $#!+ Kit - Lower Parts Kit

    Gun Nuts® OH $#!+ Kit - Lower Parts Kit

    "Oh, SH#+! Not again!" That's the typical response you shout when when you launch your lower receiver's pivot pin spring and detent across the room during install, losing them to the abyss -- halting your lower's assembly process in its tracks. Worry...

    $11.99
  • Lower Parts Kit for .223/5.56 by Spike's Tactical

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

    The mil-spec lower parts kit is adequate. It does the job it was designed for. 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. As with the...

    $71.96
  • NiB-X Lower Parts Kit, Mod 3 by WMD Guns

    WMD Guns NiB-X Lower Parts Kit, Mod 3

    You know, you can get more out of your AR shooting experience even just by making minor changes to your AR's lower parts kit. This lower parts kit by WMD Guns is mil-spec save for one detail: the trigger, hammer, and disconnector have all been coated in...

    $89.99
  • Gun Nuts® Pro Line Fire Control Group Gun Nuts® Pro Line Fire Control Group Gun Nuts® Pro Line Fire Control Group Gun Nuts® Pro Line Fire Control Group

    Gun Nuts® Pro Line Fire Control Group

    Mil-spec fitment. Improved trigger feel. The Pro Line FCG provides your AR with the perfect, all-in-one trigger upgrade. Featuring standard pin and receiver fitment, this 100% U.S.-made fire control group sports. The precision-machined, perfectly cut...

    $26.99
  • Gun Nuts® Ambidextrous Sporter Lower Parts Kit Gun Nuts® Ambidextrous Sporter Lower Parts Kit Gun Nuts® Ambidextrous Sporter Lower Parts Kit Gun Nuts® Ambidextrous Sporter Lower Parts Kit

    Gun Nuts® Ambidextrous Sporter Lower Parts Kit

    Features notched hammer and ambidextrous safety. Want to upgrade an old AR-15 with modern performance? The Sporter Lower Parts Kit from Gun Nuts does just that. This LPK features a notched hammer for compatibility with unshrounded bolt carrier groups...

    $105.99
  • Gun Nuts® Ambidextrous Pro Line Lower Parts Kit Gun Nuts® Ambidextrous Pro Line Lower Parts Kit Gun Nuts® Ambidextrous Pro Line Lower Parts Kit Gun Nuts® Ambidextrous Pro Line Lower Parts Kit

    Gun Nuts® Ambidextrous Pro Line Lower Parts Kit

    Precision components with ambidextrous safety. The Pro Line Ambidextrous 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...

    $87.99
  • Gun Nuts® Sporter Lower Parts Kit Gun Nuts® Sporter Lower Parts Kit Gun Nuts® Sporter Lower Parts Kit Gun Nuts® Sporter Lower Parts Kit

    Gun Nuts® Sporter Lower Parts Kit

    Features notched hammer and precision-fit components. Want to upgrade an old AR-15 with modern performance? The Sporter Lower Parts Kit from Gun Nuts does just that. This LPK features a notched hammer for compatibility with unshrounded bolt carrier...

    $93.99
  • 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
  • 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
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Quality, U.S.-made AR-15 lower parts kits.

The lower parts kit - which contains your AR-15's hammer, trigger, safety, and disconnector - make or break the overall "feel" of your black rifle or pistol. A poorly machined trigger and hammer will make for a poor trigger pull. We only work with the country's best gunsmiths and manufacturers to provide quality, mil-spec AR lower parts kits for all your AR builds.

Lower Parts Kits: What's Included

A complete lower parts kit includes the following components which are necessary to assemble any AR lower you fabricated with an 80% jig, or FFL-bought stripped lower receiver:

  • Hammer
  • Hammer spring
  • Trigger
  • Trigger
  • Disconnector
  • Disconnector spring
  • Buffer retainer
  • Buffer retainer spring
  • Magazine catch
  • Magazine release button
  • Magazine catch spring
  • Bolt catch
  • Bolt catch spring
  • Front pivot pin
  • Rear takedown pin
  • Hardware retaining dents
  • Hardware retaining springs
  • Pistol grip
  • Pistol grip washer/screw

How to Install The Lower Parts Kit

Need help? Follow our LPK install guide step by step.

Our guide covers every step in detail, with pictures. We cover how to install the hammer, trigger, safety, and all pins and springs, plus the other parts required to fully assemble your lower before installing your upper receiver.

What else is needed to assemble my lower?

Most lower parts kits do not include the buffer assembly, which is required for the upper receiver to operate and cycle rounds via the bolt and recoil spring. Grab a buffer tube or full buffer kit that include the recoil spring, buffer, castle nut before attempting your installation. 

As shown in our install guide, we also strongly recommend investing in a set of roll pin punches and gunsmith hammer.

Parts Kits for Other AR Calibers

Thankfully, the AR-15's various calibers all utilize the same parts kits. Even .308-receiver builds, like the .308 Winchester and 6.5 Creedmoor, use mostly AR-15 components in the parts kits. We have a quality .308/AR-10 parts kit for those builds available here. Building anything like a 300 Blackout, 9mm (AR9), 6.5 Grendel or regular old 5.56/.223 gun? Grab a standard AR-15 parts kit! They all use the same LPKs and buffer assemblies.

Upgrade that latch plate

The latch plate is the unit that retains the safety lever hardware with the buffer tube. It's also the perfect place for a quick-detach swivel sling mount. We've sourced some quality upgraded latch plates that provide multiple sling mounts and fold-out function for your buttstock and buffer, like the Sylvan Arms Folding Stock Adapter.

 


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