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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...

    Was: $49.99
    Now: $39.99
  • 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...

  • Enhanced Lower Parts Kit by Strike Industries

    Enhanced Lower Parts Kit by Strike Industries

    If your .223 or 5.56mm AR-15's lower parts kit is worn out 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 also has the...

  • 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,...

  • 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...

  • 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...

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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.

What's in an LPK?

A complete lower parts kit includes the following components which are necessary to assemble your fabricated 80% lower 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


What else is needed to assemble my lower?

Most lower parts kits do not include the buffer assembly: The components required for the upper receiver to operate and cycle rounds via the bolt and recoil spring. You'll also need a buffer assembly before you install your lower parts kit, since the buffer tube retains the spring and detent for the safety lever and the buffer retainer. We have full assembly kits that include both an LPK and a buffer assembly, plus a buttstock! The only thing you'll with one of our full kits is a lower receiver. Want everything in a single order? Grab one of our 80% AR15 lower assemblies. It includes a part skit, buffer assembly, buttstock, and unfinished 80% lower. 

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.

Installation Help (LPK Instructions!)

Need help installing your lower parts kit? We wrote an incredibly detailed step-by-step instructional guide with pictures that are easy to follow. Total installation time for new builders is approximately 1 to 2 hours with basic hand tools. Be sure to check out our Gunsmithing Tools! You'll need an AR-15 roll pin punch set and an Armorer's Wrench for installing your buffer tube.


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, 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.