Best 80% Lowers for Aspiring Gunsmiths and Shooters [2021]

by Travis Pike

April 26, 2021

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Using the words ‘built’ or ‘build’ in reference to assembling a AR 15 is a great way to get dudes with too much time on their hands riled up. They’ll argue you just assembled pieces and didn’t build anything.

You can take that out of their mouths with an 80% lower build. It’s tough to say it’s not a build if you are running a drill press, router, or Dremel to finish the dang thing. Here we’ve gathered a few of our favorite 80% lower receivers.

WHAT’S AN 80% LOWER

An 80% lower is an unfinished firearm. At the time of this writing, these kits are completely legal and can be shipped to most people without the need for an FFL. These lowers and frames are not complete and cannot function as a firearm until the end-user applies some power tool magic.

BEST 80% LOWER RECEIVERS BY CATEGORY

Best 80% Lowers

LowerDetailsCheck Price
Best AR-15

Matrix Arms 80% Lower Receiver
Matrix Arms 80% Lower
  • Simple forged design perfect for any type of rifle
  • Affordable
  • Mill it and forget it
Check Price
Best PCC

AR15 Lower Receivers AR9
AR-9 80% Lower
  • Billet designed around Glock magazines
  • Included ejector and magazine release
  • Compatible with most Jigs
Check Price
Best AR-10

F1 Firearms Lower
F1 Firearms 80% Lower
  • Unique skeletonized design
  • High-quality billet build
  • Fubar Guarantee
Check Price
Easiest Build

Polymer 80 Glock
Polymer80 Glock Lower
  • Superbly simple to finish
  • Compatible with a massive catalog of Gen 3 Glock parts
  • Better than Glock Ergos
Check Price
Best Polymer Option

Polymer 80 AR-15 Lower
Polymer80 AR-10/15
  • Polymer is easy to mill
  • Beefed up to tackle stress issues
  • Comes in a variety of colors
Check Price
Most Modular

Sig P320 FCU
Sig FCU 80
  • Swap from full size to compact to subcompact with ease
  • Easy to finish
  • Modular design
Check Price
Best for Cloners

ZR Tactical Solutions Lower
ZR Tactical Raw Forged Lower
  • Perfect for engraving
  • Mil-Spec forged lower design ensure compatibility
  • Blank canvass for any build
Check Price

BUT WHY?

We live in a time where everybody and their momma is producing AR 15 lowers, Glock frames, SIG frames, 1911 frames, and more at decently low prices. Why would one purchase a frame or lower that’s incomplete? Well, I have a few reasons why.

FUN

Building guns is fun. Assembling a AR 15 is a lot of fun, and if you want something more challenging than that, then an 80% lower is the way to go. It’s a fun thing to finish out, and the challenge of building your own firearm is both fun and satisfying.

TRADITION 

America has a long tradition of building its own firearms. All the way back to The Committee of Safety muskets, which were built underground to hide them from the British. These rifles armed the farmers turned soldiers that compromised the ranks of the Colonial forces. Keep that tradition alive and well today by building your own rifle, or pistol, or PCC, or whatever.

CLONING 

Cloning is a category of building rifles designed to clone the specifications, parts, and pieces from military, police, and even fictional weapons. When approaching it from a AR 15 standpoint, 80% lowers to allow you to get everything right, down to the markings on the lower receiver. An FN lower will also always say FN; a blank 80% lower can say whatever you’re willing to pay an engraver to make it say.

LEGALITY

As with everything related to firearms, federal and state laws differ. There are no federal laws prohibiting the private manufacture of firearms for personal use. However, state laws are a mess. The usual suspects like California and New Jersey have implemented various laws to restrict or to control 80% firearms.

Before you get your hopes up about building your own firearm, ensure your state and local laws allow such things.

As with anything, you are still bound by the NFA and Gun Control Act. You cannot manufacture firearms to sell without the proper licensing so keep that in mind.

With all this in mind, let’s dive into the Best 80% lowers and frames on the markets.

MATRIX ARMS 80% LOWER SPECS

  • Host Platform AR-15
  • Caliber 5.56mm NATO
  • Material 7075 T6 Aluminum
  • Finish Black

WHY USE A MATRIX ARMS 80% LOWER?

If you’re diving into the 80% realm, then the AR 15 rifle is one of the best places to start. The AR 15 is America’s favorite rifle and, without a doubt, its favorite 80% lower receiver.

This opens up tons of options for jigs and tooling that allows for easy milling options. With a multitude of AR 80% lowers available, you can get one of nearly any flavor. To keep all your options opened stick to the Matrix Arms 80% lowers.

These are bare-bones basic lower receivers. They are as close to Mil-Spec in shape and size as an 80% lower can get. They are forged aluminum lowers made from 7075-T6. These basic level lowers give you the maximum amount of options for milling and finishing.

Forged lowers have the most compatibility with different uppers, parts kits, and more. These lowers come anodized, and you have to do the traditional milling with either a drill press, a router, or a mini mill.

A drill press is the cheapest way. A router is a simpler way for a little more money, and the mini mill makes milling 80% lower easy. However, mini-mills are pricey. To finish this receiver, you have to mill out the trigger control area.

Five years ago, this would’ve been a challenge, but with modern jigs, end mills, and Youtube, most people can get one done without too much trouble.

The Matrix Arms models offer a lot of bang for your buck and get you going on your way to building your first rifle.

MATRIX ARMS 80% LOWER PROS AND CONS

  • Mil-spec to the core
  • Affordable
  • Has M16/M4 trigger pocket
  • Untapped bolt release roll pin holes

AR15 LOWER RECEIVERS AR-9 SPECS

  • Host Platform AR-9
  • Caliber 9mm
  • Material 6061 T6 Aluminum
  • Finish Black

WHY USE AN AR15 LOWER RECEIVERS AR9 LOWER?

As we’ve mentioned above, the AR platform is beloved, and this opens up all your options for parts, pieces, and more. With that in mind, the best 80% lower PCC you can build is an AR9.

This specialized AR lower receiver is a billet design, but it’s made to work with most AR 80 lower jigs. The billet design is purpose-built to accept Glock magazines and has a built-in ejector and magazine release designed for Glock magazines.

Dedicated parts like this ensure the gun is ergonomic and easy to use.

On top of that, the mag well is specifically designed for rapid reloads and to accommodate the slightly angled Glock magazines. As a billet lower, it has a built-in trigger guard and looks unique. It’s still made to last but will stand out. Perfect for building a braced pistol or full-sized rifle PCC.

Like a standard AR 15 80% lower, the trigger area needs to be milled out to finish the build, and since you’re going the AR route, it’s simple to find the tools and instructions to follow. This billet lower is made from the softer 6061 aluminum, so it’s nominally easier to mill.

LOWER RECEIVERS AR9 LOWER PROS AND CONS

  • Designed around Glock mags
  • Compatible with any 80 Lower jig
  • One piece with integrated trigger guard
  • Threaded screw can prove tricky for those with gorilla fingers

F1 FIREARMS LOWER SPECS

  • Host Platform AR-10
  • Caliber 5.56mm NATO
  • Material 7075 T6 Aluminum
  • Finish Raw and no anodization

WHY USE AN F-1 FIREARMS LOWER?

If you are going big with a AR 10, you might as well go cool too.

You can get a 7075-T6 aluminum made lower with some stock standard parts and pieces, mill it out, and that’s it.

Not a bad route to take, but why not go big. F-1 firearms make a slick 80% AR 10 lower from 7075 aluminum, but they do it a bit differently. This skeletonized lower has cut-outs to reduce weight and ultimately make the lower look super slick and very cool. 

This lower comes ‘raw,’ which means it lacks a finish, Which makes it easy to apply your own from anodization to cerakote. This is a billet lower, so the cuts, corners, and trim is slick and will look different from a regular old forged lower receiver.

If you are going with this cool lower, you might as well go with F-1’s other cool parts and make a unique looking blaster. That being said, you can slap on whatever AR 10 upper you choose and go big, go 6.5 Cm, or 308, or whatever. The choice is yours.

The F-1 AR 10 80% lower receiver is milled like any other AR-style platform. You mill out the trigger group section, polish it up, slap your parts in and go. F-1 Firearms even has a Fubar guarantee. If you mess up your 80% lower on the first go-around, they will sell you a second at a steep discount.

F-1 FIREARMS 80% LOWER PROS AND CONS

  • Great for skeletonized builds
  • FUBAR guarantee
  • High quality billet build
  • Extra work if you want to anodize or Cerakote

POLYMER80 GLOCK SPECS

  • Host Platform Glock
  • Caliber 9mm, 40 S&W
  • Material Polymer
  • Finish Black, FDE, Coyote, OD Green, Gray

WHY USE A POLYMER 80 GLOCK LOWER?

When I first developed an interest in completing 80% firearms, I scoured the internet trying to find the easiest palace to start.

I’m not necessarily handy with the tools, and I wanted something easy to do. After watching tons of Youtube videos, I turned to the Polymer 80 Glock builds.

These Polymer 80 designs are superbly simple to complete. I’ve done both a Glock 17 size and Glock 19 variant.

The included jib and tooling make this a simple build. You can finish it with a drill, a Dremel, or hell even handtools if you are dedicated enough to do so. It’s as simple as reducing a series of rails and drilling some holes.

It’s super easy to do, and even I finished both with minimal hiccups. These Polymer 80 frames are improvements to the traditional Glock frames. To me, they offer a better grip angle, better grip texture, a better beavertail, and a true Picatinny rail.

They come in various sizes, and to be honest, the different sizes don’t really matter in terms of difficulty. Just go with the size you’ll shoot the most. I’m a bigger fan of the Glock 17 version, but the 19 and 26 variants are sweet as well. They produce a hybrid variant that is comprised of a Glock 19 grip frame with a Glock 17 length slide, and to be honest, and this seems to be the best combination of both guns.

POLYMER 80 GLOCK LOWER PROS AND CONS

  • Extremely simple to finish
  • Compatible with a ton of Gen 3 Glock parts
  • Better than Glock ergonomics
  • Minor fitting may be required

POLYMER 80 AR-15/10 LOWER SPECS

  • Host Platform AR-10/15
  • Caliber 5.56mm NATO
  • Material Polymer
  • Finish Black, Grey, FDE, OD Green, White

WHY USE POLYMER 80 AR-10/15 LOWER RECEIVERS?

Since we already introduced Polymer 80, let’s stay on that route. Polymer 80 makes more than Glock frames. They produce polymer AR 15 lower receivers.

Polymer lowers are a controversial topic, and when they were first introduced, they were kinda pieces of crap. It seems that they’ve improved, and Polymer 80 seems to be leading the way.

Polymer 80 makes both AR 15 and AR 10 lowers in the form of the RL556V3 and the 308 80% lower receiver.

The use of polymer means they are super easy to mill and can be the perfect choice for someone with a lower end drill press or router. The Polymer 80 designs address some issues early polymer AR 15 lowers had with buffer tube housings. They beefed it up to ensure it’s a more reliable choice and kill the chances of it breaking under stress.

These lowers are thick boys but are still lightweight and designed to fit Mil-Spec upper receivers. These lowers come in a ton of different colors and are super affordable. They might be the best choice for a beginner or someone who doesn’t want to invest in a powerful drill press.

They come with the needed jig, so off the bat, you are saving anywhere from 80 to 200 bucks. The tooling is included, and all you need is the tools themselves. The Polymer 80 lowers are an interesting option, and for the first time, a company might have cracked the code for polymer AR 15 lower receivers.

POLYMER 80 AR-10/15 LOWER PROS AND CONS

  • Easy to mill
  • Durability jacked to handle duress
  • Comes in many different colors
  • No paper instructions

SIG P320 FCU SPECS

  • Host Platform Sig P320
  • Caliber 9mm, 40 S&W, 357 Sig
  • Material Titanium Nitride
  • Finish Titanium Nitride

WHY USE A SIG P320 FCU?

The P250 and now the P320 introduced a system that’s fascinating. US firearms laws are odd, and the serialized portion of a gun can vary.

While most companies use the frame of a handgun, SIG produced what they call a Fire Control Unit, or FCU.

The FCU is the serialized portion of the weapon and therefore is legally the firearm.

The polymer frame and slide are nothing more than parts and pieces and can be swapped at will without the need for an FFL.

The P320 allows you to transform a full-size handgun into a subcompact carry piece without the need to go to a gun store.

The P320 80% FCU is a very way simple way to make an uber modular 80% firearm. The SIG 80% FCU is simple to mill with the right jig. Most of the work is very simple, and it’s like a paint by numbers. Bend some rails, drill some holes, and follow the jig.

The hardest part is opening up the trigger slot with a Dremel and finishing the rails. Both take a steady hand and a good degree of patience. However, at the end of the day, the FCU is ready to be fitted in a multitude of different sized handguns.

Part of you will be invested in the work you’ve committed to complete your 80% lower, and you’ll want to use it a lot. With the SIG variant, you can move through a multitude of different firearms and enjoy your work in various capacities.

SIG P320 FCU PROS AND CONS

  • Easy to swap between semi-compact and full size
  • Easy to finish
  • Modular design
  • Patience is definitely required when building out one of these

ZR TACTICAL LOWER RECEIVER SPECS

  • Host Platform AR-15
  • Caliber 5.56mm NATO
  • Material 7075 T6 Aluminum
  • Finish Raw Aluminum

WHY USE A ZR TACTICAL LOWER RECEIVER?

As we’ve mentioned above, the AR platform is beloved, and this opens up all your options for parts, pieces, and more. With that in mind, the best 80% lower PCC you can build is an AR9.

This specialized AR lower receiver is a billet design, but it’s made to work with most AR 80 lower jigs. The billet design is purpose-built to accept Glock magazines and has a built-in ejector and magazine release designed for Glock magazines.

Dedicated parts like this ensure the gun is ergonomic and easy to use.

On top of that, the mag well is specifically designed for rapid reloads and to accommodate the slightly angled Glock magazines. As a billet lower, it has a built-in trigger guard and looks unique. It’s still made to last but will stand out. Perfect for building a braced pistol or full-sized rifle PCC.

Like a standard AR 15 80% lower, the trigger area needs to be milled out to finish the build, and since you’re going the AR route, it’s simple to find the tools and instructions to follow. This billet lower is made from the softer 6061 aluminum, so it’s nominally easier to mill.

ZR TACTICAL SOLUTIONS 80% RAW FORGED LOWER PROS AND CONS

  • Perfect for engraving
  • Mil-Spec forged lower design ensure compatibility
  • Blank canvas for any build
  • No standard bolt catch

80% DREAMS

Building rifles, handguns, PCCs, or whatever else you choose is fun, satisfying hobby. It’s educational and downright thrilling, especially for the tool inept like myself. It’s skills that not only apply to firearms but in life in general.

Why not do something that applies to both your hobby and life?

Milling out an 80% lower can be the first stop on building whatever rifle or handgun you could ever want.

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About Travis Pike

Travis is a former United States Marine Corps Infantryman and currently a firearms writer, instructor, and works in Emergency Management.

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