Choosing an AR-15 Lower Parts Kit for an 80 Lower

Posted by 80-Lower on Feb 10th 2019

Choosing an AR-15 Lower Parts Kit for an 80 Lower

There are so many available lower parts kits for your AR-15 build. We know it can get a little overwhelming parting together your build list, so today we’re breaking choosing an AR-15 Lower Parts Kit for an 80 Percent Lower build!

What an AR-15 Lower Parts Kit Includes

Whether you purchase from us or elsewhere, you should have a complete list of the required components you’ll need to finish assembling your 80 Percent Lower. The complete parts kit list can be found below. Items in parentheses indicate they’re included to complete the bulleted item.

  •         Hammer
  •         Pistol Grip
  •         Trigger
  •         Pivot & Takedown (Pins, Detents, and Detent Springs)
  •         Bolt Grouping (Catch, Plunger, Roll Pin, Spring, Retainer, Retainer Spring)
  •         Trigger & Hammer Assembly (Pins, Springs, Disconnect and Disconnect Spring)
  •         Magazine & Trigger Guard (Catch, Catch Spring, Release Button, Guard and Roll Pin)
  •         Safety Select & Pistol Grip Connect (Selector Lever, Detent, Detent Spring, Lock Washer, Screw)

#1: Classic Lower Parts Kit - $114.95

The O.G. 80% Lower Parts kit. This classic, mil-spec parts kit is compatible with any 80% lower designed to be chambered in 5.56, .223, or .300 BLK. This complete parts kit is designed to drop into any finished 80 Percent Lower without further modification.

Completing your 80% Lower with this parts kit will allow you to fit it to any complete upper and buffer system and hit the range!

#2: CMMG Lower Parts Kit (CA-Compliant) - $139.95

This California-compliant Lower Parts Kit is brought to you by CMMG, a leading AR-15 manufacturer. This kit is required for any AR-15 builders living in California. This included kit allows builders to adhere to California’s rigorous “Assault Weapons” restrictions with the inclusion of the patented ARMagLock system.

The ARMagLock system allows your California-built AR-15 to be legally classified as a weapon with a fixed magazine. The ARMagLock allows for quick and intuitive disassembly and reassembly of your upper and lower, allowing for quick magazine changes while staying legal!

#3: CMMG AR-10 Lower Parts Kit - $104.95

Ever wanted to own the fabled AR-10? Expensive barriers of entry have been knocked down thanks to the DPMS Gen 1 80% Lower! This .308-chambered 80% lower allows for the completion of an AR-10-like rifle.

Keep in mind, though, that DPMS’s own .308 platform is not the same as ArmaLite’s platform – components are not interchangeable. As such, you’ll need the CMMG AR-10 Lower Parts Kit to complete your .308 80% Lower.

What about the AR-9 Lower Parts Kit?

Rest easy – if you’re ready to build an AR-9, all you’ll need is the standard AR-15 Lower Parts Kit! The same rules apply for California-compliant AR-9 build, just grab CMMG’s CA-Compliant Lower Parts Kit.

Drop-in Trigger Kits

If a standard, mil-spec trigger isn’t for you, don’t worry! We offer a variety of competition- and performance-spec drop-in trigger kits. These drop-in triggers are compatible with any corresponding parts kit.

For an affordable upgrade, check out the RA-140 Super Sporting Drop-in Trigger. This budget-friendly trigger only costs $129 and affords a crisp break with little take-up, creep, or overtravel. A light, 3.5-pound pull provides a great balance of precision and safety.

Want the best trigger on the market? The RA-535 Advanced Performance Drop-In Trigger was built to tolerances of one-millionth of an inch, making it one of the most precise and perfected AR-15 triggers ever.

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.