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AR Lower Parts Kit

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  • Sale
    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...

    Was: $39.99
    Now: $29.99
  • 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
  • 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
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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.

 


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.

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