Best AR-15 Lower Receivers [2021]: Budget to Baller

We know what you’re thinking right now:

Why are some AR-15 lower receivers $45 and some $200+?

How do I know what’s the best for me?

It’s not as intimidating as it seems, so don’t worry!

And we’ve built our fair share of AR’s with a variety of lowers!

We’re going to cover the differences in manufacturing, materials, and weight to help you pick the best lower for your budget and build.

Manufacturing Processes

The overwhelming majority of lower receivers are made of aluminum.

While there are other options such as steel, titanium, and polymer, we’ll focus mostly on the three ways aluminum is made into an AR-15 receiver.

We’ll touch on polymer also, but I’ll try to be brief.

First, what are those numbers in front of the aluminum?

6061-T6 vs 7075-T6 Aluminum Receivers

There are two types of aluminum alloys that are used in making lowers.  6061-T6 and 7075-T6.

So, what’s the difference?

Simply: strength and corrosion resistance

7075-T6 is nearly twice as strong as 6061-T6.  Naturally, there will be a cost difference between the two.

However, 6061 is more corrosion resistant.  But unless your receiver is bare aluminum, this part shouldn’t affect your decision too much.

When planning your build, think about how much that strength is worth to you.

Want our advice? 

The difference nowadays between 7075 and 6061 is so minimal that we like the peace of mind that comes with 7075.

But if budget dictates 6061…you’re fine too.

Now onto the three ways of manufacturing a receiver.

Cast Aluminum

The casting process is very basic.

Pour the molten aluminum into a mold and, once cooled, you have a lower receiver ready for final machining.

Since the aluminum is poured into the cast as a liquid the final product will have a loose crystalline structure making it the weakest form of the three types of aluminum.

It is still strong enough for the receiver to be perfectly safe without fear of malfunction.

However, it is the least desirable of the processes.

Billet Aluminum

Think of it this way, the manufacturer is Michelangelo and the billet bar stock is the marble.

The lower starts out as a block of pure aluminum that ends up on various machines that mill it into a finished product.

It is just sculpting with metal.

Because the aluminum remains solid billet lowers are stronger than cast and have a finer finish.

If you’re looking to build a “show gun” consider a billet lower!

They also have the added benefit of being easily customized by manufacturers since they start with raw aluminum.

This allows for creative changes to be made such as a skull-shaped magazine well, built-in trigger guards, and extra machining for weight savings.

This Seekins lower ($250) shows what cool things can be done with billet.

Forged Aluminum

The strongest and most common of the three types.

Take some aluminum and smash it into submission.

That’s essential what’s going on in this process.

Machines press a block of aluminum into the desired shape and then it gets machined to finish it off.  The compression of the aluminum increases its strength.

This is ideal for an AR-15 you plan on using often and hauling around with you.

Ambidextrous Lowers

This is a term you’ll see pop up now and then generally on premium lowers.

If you see a brand making lowers for one price, then see some lowers for 2x or 3x the price from the same brand — chances are the expensive ones are ambi.

Ambidextrous lowers mean they have controls on both sides of the lower. How, what, and where depends on the lower.

There are no standard naming conventions for these features so you’ll often have to inspect each lower on their own to see what type they are.

The bare minimum of an ambi lower is one that has a safety selector on both sides.

A step up from those will have a magazine release AND a safety selector on both sides.

Good ones will have the mag release, the safety, and a bolt release on both sides.

The best, and in my opinion the only ones that should have the right to call themselves ambidextrous, will have the mag release, the safety, the bolt release, and a bolt catch on both sides.

Note the difference between a bolt release and a bolt catch. Often an ambi lower will let you release your bolt from both sides, but will only let you lock it back from one side. That’s useful, but it isn’t the best.

Okay, But Why?

Simple, so you can use all of the controls from both sides of the rifle.

If this is purely a range toy, then ambi really doesn’t matter. But for competition, SHTF, or home defense — I really recommend looking at ambi lowers or at least adding a ambi safety and mag to your normal lower.

You never know when you’ll be hurt, when you’ll need to switch sides when you’ll have your hands full with something or someone els.

The ability to manipulate your rifle from both sides have benefits that will only present themselves when you truly need them.

Polymer Lowers

Because of the growing popularity of polymer lowers, it’s worth talking about the pros and cons, how they are generally made, and why you might want one… or might not want one.

History Of The Polymer Lower

Surprisingly, polymer lowers really aren’t new. Colt was playing around with the design in the late ‘60s, it didn’t get past the testing phases — but they still were the first.

Polymer lowers would languish and be mostly ignored for several decades but the idea eventually came back.

Plastic is cheaper than aluminum, easy to work with, and lighter. So on paper, it makes for a good material for a non-wear part like the AR-15 lower receiver.

Is It Strong Enough?

This is where we run into some issues. If you take the specs for a standard AR-15 lower and try to just make it out of polymer, you’re going to have a bad time.

Failure points like the walls around where the safety detent goes are very thin and prone to breaking.

Where the buffer tube connects to the lower is another weak point, and even the threads for the buffer tube is often a problem and wear quickly if the buffer tube is replaced more than a few times.

There are other weak points but you get the idea.

To combat this, you need a lower that is designed to be a polymer lower. You can’t just take AR-15 lower specs and switch to plastic.

Overall though, the problem with these designs is that they are just too much weakness for not enough gain.

A standard aluminum stripped lower is about 8.5 ounces, a polymer stripped lower that is decently designed is about 5.5 ounces.

3 ounces really isn’t much weight savings and pre-covid the price wasn’t much different either, maybe $10 difference.

The Monolithic Polymer Receiver

Here is the game-changer.

While the difference between a stripped Al lower and a striped poly lower might only be a few ounces, when you make the entire lower — the grip, the stock, and the receiver, out of polymer, then you can save some major weight.

A complete aluminum lower (buttstock, grip, LPK, trigger) weighs around 2.5 to 2.8-pounds. Something like the KE Arms KP-15 complete lower (buttstock, grip, LPK, trigger) weighs 1.7-pounds.

A full pound or close to it is some real weight savings.

Making the entire lower out of polymer also allows you to design it so that everything is strong enough, often stronger than an aluminum lower because it’s all one part.

There are some downsides, but there are a lot of upsides too.

Sadly, there are very few options in this category — but more on that later.

Best AR-15 Lower Receivers

Most websites are going to tell you to weigh it out and decide on your own.

Here at Pew Pew Tactical, we’d rather show you some examples and talk about them.

Frankly, we won’t cover cast lowers.  For two easy reasons: they’re weak and I think they’re ugly.  Never have I used a cast receiver in a build and don’t think you should either.

Now let’s get on with our top picks!

To be clear though, these are not in any set order. All of them are great, some are better than others for different reasons.

1. Palmetto State Armory

Simple forged lowers for a great price, they also offer a host of complete lower options for basically every type of AR-15 you can think of.

We’ve used and reviewed just about every AR-15 and AR-10 rifle that PSA makes and their lowers have never given us even a hint of a problem.

They even have some awesome limited edition lowers, such as their “Space Rider” stripped lower!

If there’s a current event or meme…they’ll have you covered.  On the flipside…they also have “stealth” lowers that I like.

Otherwise you can’t go wrong with their regular ones.  And if you don’t feel like building the lower…check out their complete lowers.

What’s your take on PSA lowers?

2. Anderson Manufacturing

Here it is, the Honda of lower receivers.

Anderson Lowers are cheap ($42 for stripped and $120 for complete), they’re forged 7075-T6, and they’re often available.

My accuracy testing lower uses the Anderson and Hiperfire trigger (Best AR-15 Triggers).

I have used their lowers on countless builds and have had zero issues with them.

If you scratch it while building, who cares?  Do not let the price fool you, these are quality basic lowers good for 90% of your potential builds as a hobby shooter.  I have four of these in my safe right now just waiting to be built.

Plus there’s also “stealth” versions where they don’t have the horse logo if that makes you feel better!

3. Aero Precision

My buddies and I have built at least a dozen ARs with Aero lowers.  They are all running just fine.

Aero Precision lowers ($90) are just like Anderson’s (forged 7075-T6) but their logo is better looking.

You can pair it with an Aero stripped upper receiver too which is our current favorite.

And every once in a while Aero will release their Pew Pew lower ($105).  Don’t worry it doesn’t automatically make you able to switch to Pew Pew Pew…though I can dream.

PLUS…there’s an adjustable screw for Gen 2 models that makes a tighter fit with your upper…no more rattling around!

My newest competition build utilizes an Aero FDE Gen 2 lower receiver.

Can’t wait for some future builds with more of them…my personal favorite for most builds.

Oh…and now we have a full review on Aero’s M4E1 uppers and build kits using…you guessed it…Aero lowers.

Check out the full review of the M4E1 and all the parts used in the build.

4. Battle Arms Development

How cool is this?

The B.A.D. lightweight lower ($269)  looks like something from Starship Troopers.

Lightweight builds are all the rage right now.  Compare the BAD weight of 6.84-ounces to Anderson’s 10.88-ounces and you’ve shed a quarter-pound in just the lower!

Also made of 7075-T6 aluminum, this lightweight beauty would be great for someone building a race gun.

5. F1 Firearms

This might not be the lightest at 9.4-ounces…but it’s definitely the coolest looking.

But one thing is for sure…F1’s billet lower ($230) brings some style to the competition shooting game.

Couple it with an even more insane upper receiver to save a ton of ounces.

6. Lewis Machine & Tool Company MARS-L

A truly ambi lower, the MARS-L is in our editor’s opinion the greatest lower on the market right now. 

This is the same pattern of lower that New Zeland adopted as their standard issue rifle and it comes with some great features.

First and foremost, this is truly completely ambidextrous. Every control can be used from both sides, including the bolt release and stop.

They are also proprietary to the MARS-L, not just aftermarket parts slapped on a standard lower sold for 4x the price.

Downside of all of that is that these are not cheap and they are often hard to find. LMT often has these back-ordered for 6 months or more at a time. If you see one for sale, get it fast!

They never stay on the shelves for long.

7. KE Arms KP-15 Monolithic Polymer Lower

These are barely on the market and almost none of them are in the wild just yet.

And as such, we have no personal experience with them. But we do have a couple on order so when they get here… we’ll let you know.

That said — the KE Arms KP-15 was designed by KE Arms with the help of Ian McCollum and Karl Kasarda from InRangeTV based on their What Would Stoner Do 2017/2020 projects.

If you’re interested in those, I strongly recommend their videos on YouTube because it’s an awesome project.

Basically, this is a monolithic polymer lower that is designed to be such in every way. From the ground up this is meant to be exactly what it is. Strong, durable, lightweight, and reasonably priced.

Based on the testing and feedback we’ve read about it — we pre-ordered one. We’ll update with more info once we get done testing it!

8. Brownells Retro Lowers

Okay, there really isn’t anything special about these lowers, except that they are patterned after lowers from long ago. The AR-15 lower has changed in small ways over the years and these are throwback lowers to those bygone designs.

Would I put one on a modern home defense rifle? Not unless I couldn’t find a normal lower.

But I would use them on a clone build like an old school M16A1, XM16, or early Colt M4 build!

They look good, they’re well made, and they’re fun. Plus, they are a lot cheaper than trying to source originals.

9mm AR-15 Lowers

If we had to choose one…it’d be the PSA PX-9 lower that takes Glock mags.

See how it already looks different from regular AR-15 lowers? It’s got an ejector built in and a longer mag release.

We cover all the differences you’ll see in pistol caliber AR lowers and the rest of our choices in Best 9mm AR Lower Receivers.

Others

But the ones I see at the gun store are not on the list?

To provide you with information and direction, the above recommendations were selected without persuasion.

There are countless other places who manufacture and machine lower receivers.  There are three things you should keep in mind when shopping around for them: material, process, and reputation of the manufacturer.

A good place to start for manufacturer reputation is with our AR-15 Buyer’s Guide.  If their complete rifle is good…chances are their lowers are good too.

You can then cross-check against what is in stock at your local store so you can save on shipping.  Or check out the full list of lowers from Brownells and Rainier Arms (for cooler billet ones).

Conclusion

Ultimately you’ll get a feel for each company and find favorites, as I have.

Some people prefer different logos or roll marks, some have brand loyalty, and others only worry about the price of the lower.

There are many who choose a forged lower over the pricier billet lowers using the simple mantra “a lower, is a lower, is a lower.”

If I had to choose one lower for the rest of my builds…I’d go with the Aero.

That’s what Uncle Sam taught me was the KISS method: Keep It Simple, Stupid.

Now that you’re armed with enough knowledge to help you sort through the haystack and narrow your search get out there and find what works for you.

Finish your lower with our Best Lower Parts Kits and also the AR-15 Resource Guide for all other parts.  Or…fancy completing an 80% lower receiver?  Check out our Best 80% Lowers & Jigs article.

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