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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, New Jersey, New York, Pennsylvania, 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.

80% Lower Receivers & Frames Compared

Posted by 80 Lower Jig, Co. on Jun 4th 2020

80% Lower Receivers & Frames Compared

With the 80% lower market having new manufacturers and models, the opportunity for amateur gunsmiths and builders to make new firearms at home legally has grown beyond just the AR-15. This updated guide compiles the latest and greatest available 80% receivers and 80% frames available today.

Not sure what any of these things are? Start here: What's an 80% Lower?


Types of 80% Lowers (AR Platform)

1. Forged AR-15 Lower, Anodized or Raw

Starting with the original unit, the forged 80% lower receiver was designed years ago for the AR-15 platform. It mirrors the dimensions and shape of a stripped receiver -- the only part of the AR considered a firearm -- in every way. The fire control cavity requires cutting and drilling for the trigger, hammer, safety, springs, and pins to hold every inside. These units can be purchased " raw", allowing you to add a custom finish, or anodized with a mil-spec matte black protective coating.

Build compatibility

  • AR-15 chambered in 5.56/.223
  • AR-15 chambered in .300 Blackout
  • Can be converted to 9mm, .22 LR with aftermarket parts
  • Works with all standard retail AR-15 parts and uppers

Features & Specifications

  • Made of 7075-T6 forged aluminum (mil-spec)
  • Raw or type III hardcoat anodized finish

2. Billet AR-15 lower, Anodized

The  billet 80% lower receiver is an upgraded version of the typical forged unit. This option is a few bucks more expensive but it returns the extra investment by making the lower parts kit install much quicker and easier: The roll pin fittings for the takedown detent and bolt catch have been replaced with threaded holes:

This unit also ditches the fittings and pins for installing a trigger guard. The guard's machined right into the receiver from the factory. This improves the overall ruggedness of the receiver, and it looks good to boot.

Build compatibility

  • AR-15 chambered in 5.56/.223
  • AR-15 chambered in .300 Blackout
  • Can be converted to 9mm, .22 LR
  • Works with all retail AR-15 parts

Features & Specifications

  • Made of 6061-T6 billet aluminum
  • Type III hardcoat anodized finish
  • Threaded fittings with integrated trigger guard

3. Billet LR-308 lower, Raw or Anodized

The AR-15 is arguably America's favorite rifle, but some shooters want more firepower. The bigger AR-10 from ArmaLite (or the modern SR-25 from Knight's Armament) is what comes to mind for most, but these military-issued rifle platforms cost thousands of dollars. However, you can build an affordable .308 AR that looks and performs just like the AR-10 and SR-25 by going with the  LR-308 80% lower. Available raw or anodized, the .308 lower is patterned off DPMS Panther Arm's LR-308 platform.

LR-308 vs. AR-10 Compatibility

To answer a common question: The LR-308 lower is not compatible with the AR-10's and SR-25's upper receivers. The upper receivers are shaped differently, so you can't install an AR-10/SR-25 upper on an LR-308 lower:

The .308 upper receiver you must pair with this lower features a rounded edge where it meets the lower receiver and buffer tube housing. The AR-10 and SR-25 uppers feature a straight-angled edge.

Build Compatibility

  • AR chambered in .308 Winchester
  • AR chambered in 6.5 Creedmoor
  • AR utilizing DPMS .308 components
  • Works with LR-308 lower parts kits
  • Does not work with AR-10/SR-25 parts

Features & Specifications:

  • Made of 6061-T6 billet aluminum
  • Raw or type III hardcoat anodized finish
  • Threaded fittings with integrated trigger guard
  • An affordable alternative to the AR-10, SR-25

4. Billet AR-9 lower, Anodized

The AR9 80% lower is one of the first "by-design" receiver blanks that's capable of chambering 9mm Parabellum without the need to invest in a custom "box conversion" for a standard AR-15 receiver.  This is a proprietary lower that accepts Glock 9mm magazines and AR9 barreled uppers equipped with a G-9 blowback bolt. The magazine well is wide enough to fit a double-stacked 9mm magazine properly. To ditch the need for a box conversion, the receiver also comes with a 9mm ejector (the hook pictured above) installed. The receiver works with a standard AR-15 buffer tube and recoil spring, but you'll need to buy a 9mm (heavy) buffer to get your new PCC cycling correctly. Everything else about this lower is standard, too. It works with a mil-spec AR-15 lower parts kit and trigger.

Build compatibility

  • AR9 chambered in 9mm Parabellum
  • Works with Hybrid G-9 bolt carrier group
  • works with factory, aftermarket Glock magazines
  • Does not work with 9mm Colt SMG magazines
  • Works with retail AR-15 lower parts kits

Specifications

  • Better alternative to 9mm box conversion
  • Custom magazine release lever
  • Made of 6061-T6 billet aluminum
  • Type III hardcoat anodized finish
  • Factory-installed 9mm ejector
  • Integrated trigger guard

5. Polymer80 AR-15 and LR-308 Lowers and Jig

Nylon-reinforced polymer has played a big role in the development of modern firearms. SMGs, popular handguns like the Glock, and now rifle receivers are being built from this material. A few years ago, Polymer80 introduced their own take on the AR-15 and its related receivers with high-strength, nylon-poylmer 80% lowers. These units weigh a fraction of a billet or forged receiver, coming in at around 0.3 pounds. For their light weight, they're proven to work just as well handling 5.56 NATO, .223 and even .308 cartridges.

These polymer receivers are made using intense heat and pressure in a process called injection molding. The nylon polymer is melted, forced into a receiver mold and allowed to cool. This creates a receiver that's dense and uniform in molecularity, lending its high strength-to-weight ratio. The polymer receivers are easier to cut and machine than a unit made from aluminum, too. Because of this, the 80% jig required to complete the lower is included, as is the tooling. The jig is disposable, making the kit affordable. If you don't already own an 80% jig or the tooling needed to complete this project, the polymer jig-and-lower combo will be the most affordable way to get your hands on everything you need.

Build compatibility:

  • AR-15 chambered in 5.56/.223
  • AR-15 chambered in .300 Blackout
  • Can be converted to 9mm, .22 LR
  • Works with all retail AR-15 parts

Features & Specifications:

  • Made of composite, solid-core nylon polymer
  • Includes bits and jig required for completion
  • Easiest AR-type 80% receiver to cut and drill
  • Most affordable lower and jig combo overall

6. JMT AR-15 Polymer 80% Lower and Jig

JMT is another polymer 80% lower manufacturer, like Polymer80. Their receiver boasts a few more aesthetic appointments, like a magazine well that features the Magpul PMAG design. Besides the mag well, the JMT receiver functions the same as any other AR-15 lower. Picking between JMT and Polymer80 ultimately comes down to personal preference.

Build compatibility:

  • AR-15 chambered in 5.56/.223
  • AR-15 chambered in .300 Blackout
  • Can be converted to 9mm, .22 LR
  • Works with all retail AR-15 parts

Features & Specifications:

  • Made of composite, solid-core nylon polymer
  • Includes bits and jig required for completion
  • Easiest AR-type 80% receiver to cut and drill
  • Most affordable lower and jig combo overall

Stealth Arms 80% 1911 Frame

You can build any firearm at home, as long as it isn't an automatic weapon or NFA item. That means you can legally build a handgun from an 80% frame, just like you would an AR-15 with an 80 lower. Stealth Arms is one of the first companies to introduce  frame blanks for the 1911. Unlike the original steel design, these frames are made from aluminum to make machining easier. They're also noticeable lighter.

These frames are completed by cutting the barrel seat and slide rails with a  handheld cutting jig, also available from Stealth Arms. You'll need to drill the hammer and trigger pin holes, completing the frame. Once finished, the frame's compatible with regular 1911 parts from any manufacturer. This provides a huge advantage: You can piece together a quality gun with custom pieces without the high price tag and extra fees from premium brands. Complete kits that include all the parts to build a 1911 are available, too.

Build compatibility

  • 1911 Commander chambered in .45 ACP & 9mm
  • 1911 Government chambered in .45 ACP & 9mm
  • No 1911 Officer 80% frame is currently available
  • Completed frame is compatible with retail 1911 parts

Specifications

  • Made of 6061-T6 billet aluminum (weighs 50% less than steel frames)
  • Can be completed with a hand drill (frame cutter supplied with jig)
  • More affordable way to own a custom 1911

GLOCK-Compatible "P80" Frames and Jigs

Legally, these frames can't be called GLOCK frames. But they're 100% compatible with GLOCK components, and when finished and assembled, they look and function all the same. Introduced by Polymer80, these  frames and build kits require some basic cutting and drilling, too. Since they're made of polymer, they're incredibly easy to complete. 

Cutting the slide rail area can be done with snipped or hand files, and drilling the required pin holes for the internals is done with a hand drill. Like Polymer80's AR receivers, these include the required jig for completing the frame. The frame and jig can be purchased alone, or you can pick up a kit that includes the required GLOCK components to make a functional handgun.

Build compatibility

  • PF940C compatible with Glock 19/32 components
  • PF940v2 compatible with Glock 17/34 components
  • PF940SC compatible with Glock 26/27 components

Specifications

  • Made of composite, solid-core nylon polymer
  • Easiest 80% pistol frame to cut and drill by hand
  • Most affordable pistol frame and jig combo

Sig Sauer P320 80% Chassis and Pistol Build Kit

Sig's new P320 modular handgun -- which can be modified in size as well as to shoot different calibers -- received the 80% treatment lately. Unlike the P80 frame, 1911, and AR platform, the 80% component of the P320 is the fire control unit. 

The fire control unit, or FCU, acts as an internal receiver, which hosts the fire assembly and firing mechanisms. These P320 kits come with the jig and instructions for completing the FCU to make it into a functional firearm. Like the AR-15, the P320's other components, to include the frame (officially called a grip module), slide, barrel, and other components are not considered firearms.

Build Compatibility

  • Full-Size
  • Carry
  • Compact
  • Subcompact
  • .357 SIG
  • 9mm Parabellum
  • .40 S&W

Specifications


Summary

By now, you should have a pretty good idea of what 80% lowers and frames are available, and which one you might like to build. We recommend you next learn about the important "other half" of this project before getting started by reading our intro guide to 80% jigs. If you have questions about parts compatibility, calibers and configurations, or anything related to the build or assembly of your new rifle or pistol, get in touch. You can call or email us. We build guns from the very parts we sell in our spare time, so we're happy to help.

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.

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, 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.