AR Lower Parts Kit
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 spring
- 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 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.