Best AR-10 Lowers For Your Next Build

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A little while back, I told you wonderful folks about what I considered to be the best pre-built AR-10’s around.  In that article, I made a promise to come back in the future and talk about the best AR-10 lowers for building your own custom rifle.

Well, that time is now.  I know a lot of you, like me, enjoy building a rifle almost as much as shooting one, so being able to buy a lower and turn that into a full functioning firearm is really satisfying.

c clamp grip ar15
Also, if you want to seriously compete with an AR, it’s very likely you’ll get more bang for your buck (pun absolutely intended) by building a gun instead of buying one.

I also know that, like me, many of you would rather save money and put in a little extra work to get something you really want, instead of paying more for something that’s almost-but-not-quite perfect.

So, if you’re looking to build an AR-10 from scratch, or at least build a complete lower, here are the lowers I’d suggest for your build.  (Be sure to give a shout to your favorite lower in the comments, even if it isn’t mentioned here).

Now, unlike AR-15 Lowers, not everybody with a CNC machine makes AR-10 lowers.  Of course, there are plenty of other lowers out there that will work just fine.  However, I’m on a limited budget and I don’t like telling people to buy things I haven’t tested, or at least gotten my hands on.

Almost a decade of machining experience makes it pretty easy to tell sloppy work from quality, and while there are a few lowers I’ve looked at that I wouldn’t use unless I have to, I’m sure there are plenty of other lowers out there that are worth your time.

I especially want to hear from experienced shooters and builders out there that have other lowers they like, so be sure to hit up the comments if you have a good suggestion.

Alright, enough stalling.  Let’s talk about why I picked these lowers in particular.

My Criteria

Reasonably speaking, a modern lower from a quality manufacturer shouldn’t have any problems.  Machining costs are going down, and machining precision is going up, so anyone that’s competent and properly licensed can turn out a functional AR-10 lower.

AR-15 Lower Receiver
ATF aside, these things honestly aren’t hard to make provided you have the tools to do so.

There are no moving parts, and you can even buy 80% lowers without going through an FFL and finish the machining yourself, at home, with nothing fancier than a jig and a drill.  Of course, I recommend things like a vise with polymer jaws, a drill press, a mill, etc, but I’ve absolutely seen it done with basic tools, especially when it comes to polymer lowers.

That being said, I wouldn’t buy from Uncle Ruckus’ Discount Machine Shop, or any manufacturer of that ilk.   No disrespect to any smaller outfit, or to anybody who happens to have a CNC machine out there, but my gun budget is limited and I don’t have the funds, time, or energy to spend on somebody that doesn’t have a solid reputation.

However, if you think you’ve got the best lowers in the game, drop me a comment below.  I’ll be more than happy to tell the world my honest thoughts on how your lowers stack up against the big dogs.  Just be prepared for my very honest thoughts.

I also want a forged or billet lower.  Like our editor Eric, and many others, I’ve never found a cast lower to be as nice as a forged or machined billet lower, and they’re inherently weaker.  Granted, they’re still stronger than a poly lower, but if you’re going to pay the extra dosh for a more rugged lower, you may as well get one that’s going to survive whatever you throw at it (or throw it at).    

With that out of the way, let’s look at the lowers themselves.

Best All Around: Aero Precision M5 Lower

Best AR-10 Lower
Aero Precision M5 Stripped Lower Receiver

Aero Precision M5 Stripped Lower Receiver

I have made no secret that I love Aero Precision’s stuff.  I’ve used their uppers, lowers, bcgs, and handguards extensively and the only complaint I have is that I sliced my finger on a random staple in one of their packages one time.

Other than that issue which was like, 92% my fault, I’ve never once had an issue with an Aero Precision product and I have two rifles with almost all 5,000 rounds each through them.  The barrels are the only things I have any plans to change, and that’s just because of normal wear.

Also, for someone like me with lots of access to lots of guns (yes, my job is awesome) its rare for me to have guns that I come back to over and over and over.  The exceptions are my two Aero competition guns and my Glock 19 that is my go to carry piece.

The Aero M5 Lower ($185.00) is absolutely worthy of the industry-leading reputation Aero has garnered for themselves.  It truly is a triumph of manufacturing and firearms design.

I own two of them, both purchased with my own money, which is high praise from anyone who gets gun stuff for free.

This lower has a number of features I like and they are what put it over other similarly-priced lowers.

Aero M5E1 Accuracy, Mrgunsngear
Aero M5E1 Accuracy testing from Mrgunsngear

First, it has an integral trigger guard, which is one less part you have to worry about, and also it makes for a stronger overall lower.  This is a subjective thing overall because some folks would rather put in the trigger guard of their choice, but I personally like a nice, solid, integral guard.

Next, it has a really nice polymer-tipped set screw that lets you adjust the fit your upper to eliminate some of the pesky wobble you’ll get given the machining difference between manufacturers.  

Of course, you can minimize the need for this with a matched Aero M5E1 upper, but it’s still nice to have that adjustment to really fine-tune things.

It also works with easy-to-find AR 308 parts and mags, so you have a lot of aftermarket options for pretty much everything.

You can also get them in super awesome builder’s sets from Aero.  If you go that route, you can pick up a receiver set and handguard in a really sweet color like the “Spent Brass” set below.

Aero Spent Brass Builder Set

Aero Spent Brass Builder Set

Prices accurate at time of writing

Finally, be sure to check out Eric’s review of the full M5E1 rifle that’s also available if you want a fully built gun instead of a lower.

Aero Precision M5 AR-10
Aero Precision M5 AR-10 Complete Rifle

What’s your take on the Aero M5 lower?

Readers' Ratings

5/5 (129)

Your Rating?

Best For Getting Going Quickly: Seekins Precision SP10 308 Receiver Set ($879.00)

When you build rifles like I do (read: like a crazy person preparing for the end of days) sometimes you just want a complete setup that requires as little work as possible, while still leaving yourself the room to slap in all the parts you really want.

Enter the Seekins Precision SP10 308 Builders Kit.

This kit, like that awesome Aero builder’s kit, will allow you to get a perfectly mated and matched upper, lower, and handguard all at once.

seekins sp10
The machining on this is absolutely flawless.

Full disclosure: If there’s a part I need for a rifle that Aero doesn’t make and Seekins does, it’s probably going to be a Seekins part that ends up on my gun.

The barrels in those mostly-Aero rifles I talked about?  Those are Seekins.  The gas blocks too, which I highly recommend if you’re going to be running a can on your new build because the adjustability on their suppressor-friendly blocks is awesome and requires the minimal amount of futzing to get dialed in.

Bottom line: Seekins is one of the best manufacturers in the industry.  Glen Seekins and his company have been making great rifles and great parts for a lot of years, and this receiver set absolutely reflects that.

Honestly, from more than a few feet away, you could be forgiven for thinking the upper, lower, and handguard were all one solid piece.  The upper definitely has that monolithic look (and stiffness) to it.

The only thing I will say is that, because of the exacting nature of Seekins machining, you may have to spend more on your upper if you go with one of their lowers and want something with the minimum amount of fitment issues.  

Of course, these issues can be eliminated entirely if you just buy all your major parts at once like you can here.

Also, if you’re reading this and suddenly jonesing for a completed rifle, worry not!

You can buy a completed rifle (minus optic) that’s made with all Seekins parts where available, and the fit and finish is as good as any in the industry.  You can check the full SP10 .308 rifle out below.

I’ve yet to spend money that kind of money on an AR-pattern rifle without building it myself from the ground up, but if I was going to buy a complete semi-auto .308 that I had to take into battle, it would either be this Seekins rifle, or the LWRCi REPR I love so freaking much.

LWRC DI Grey
It…it’s perfect.

Armalite AR-10: Best For Traditionalists

Armalite is the real progenitor of the AR-10, and the Armalite style of AR-10 is one of two rifle patterns that have become the industry standard (the other being the DPMS style of the other lowers we’ve talked about so far).  

The original AR-10 is a truly rugged design, but it does lack the refinement of some more updated modern designs.  It’s also much harder (and more expensive) to buy spare mags for it.

Of course, the people that kicked off the AR-10 design do make one hell of an AR-10, as you would expect, and their lowers are a big part of that.

These lowers are great if you want to build a rifle similar to something you served with, or just want something that’s more authentic to the original AR-10 design.  This is also the route you should look at going if you have a bunch of AR-10 style mags already on hand, or know of where you can get some.  

Armalite AR-10 Lower

Armalite AR-10 Lower

Prices accurate at time of writing

As a note, always pay attention to which style of AR-10 mags you’re buying, because if you have an Armalite style rifle, you can’t use SR-25 style mags in it, and vice versa.

Best Budget Choice: PSA Gen 2 PA10 .308 Classic ($159.00)

PSA Gen 2 PA10 .308 Classic Complete Lower

PSA Gen 2 PA10 .308 Classic Complete Lower

Prices accurate at time of writing

If you want a solid, functional (if not particularly beautiful) lower and the lowest price, Palmetto State Armory is going to be the place to go.  

In general, PSA is a fan-freaking-tastic place to look for cheap guns and parts in general (they have some black magic voodoo involved in their prices).  

Despite the price, PSA’s in house brand is perfectly serviceable, and totally adequate, you just lose out on some of the bells, buzzers, and/or whistles from more expensive brands.  Then again, this lower is priced at less than almost every other product on this list.

Oh, and did I mention it’s a complete lower?  Yeah.

Stock, grip, parts kit, fire control, trigger, whole deal.  And its still almost cheaper than any other option out there, and certainly cheaper when you compare the prices of completing this lower versus any of the others.

Personally, my first ever AR back in my “broke college writer” days was a PSA monstrosity I built in my parent’s garage.  That rifle has since harvested deer and won local 3-Gun events.

3gun shooting competition
Is it as pretty, accurate, or reliable as this gun? No. Did it beat an awful lot of guns that look like an awful lot like this for a third the price?  You bet your ass.

Make no mistake, you absolutely should not sleep on these guns and lowers, even though they are cheaper than the competition.  Is the machining as tight?  No. Is a stock PSA gun going to compete with a stock Noveske, Seekins, or LWRC rifle?  With equally skilled shooters, no.

Will it go bang absolutely every time and be “accurate enough” for most purposes?  Absolutely.

What’s more, it’s easy to justify building say, a .308 version and a shiny new 6.5 Creedmoor version as well, and you can just about get both for the price of one of the competitors rifles.  If you’re a quantity over quality person, this is definitely the route to go.

Parting Shots

That does it for the AR-10 lowers!  I hope this helped your quest for the perfect lower for your next build.  I would happily stand behind guns built on any of these lowers, and I’d be very nervous about standing in front of them.

Which one of these lowers are you most likely to use?  Is there a lower that might be better in a particular category than the ones I picked?  Let me know in the comments below!

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Chris Cox
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Chris Cox

Any ideas where you can purchase AR10 308cal Strip lowers with Custom Serial Number and 100% ready to put together?

Clint
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Clint

I recently purchased a PSA 6. 5 Creedmoor Gen 2 upper and I’m looking for advice on what type of lower will be best compatible with this? From what I found out most of the AR-15 parts will work other than mag catch bolt catch pivot and takedown pin detents and springs are all the same looking for lower build information any information provided will be greatly appreciated!

Practical Rifleman
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Practical Rifleman

I may be missing something, but I am not seeing what is inherently better for a lot of the parts between a many of these “high end” companies and “average companies”. If better equals “more bells and whistles”, then yes, high end companies are “better”. But a lot of what they are claiming is better, is actually just those bells and whistles that do very little for the actual functionality of the firearm. For example, Seekins Precision claims that their SP223 Gen2 “far exceeds mil-spec requirements”. However, it is a billet lower, not a forged lower, which is the mil-spec… Read more »

David, PPT Editor
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I think you’re confusing “milspec” with “best”. The military requirements for items are rarely the best way to do things, they are rarely the most durable or well made and they are always made by the lowest bidder. Yes, a forged lower is metallurgically stronger than billet – but only very slightly and I have never come across a test or even a story about a billet lower failing when a forged lower did not. When it comes to QC and manufacturing I would absolutely believe that Seekin’s Precision outpaces milspec in every way. As for barrels, the milspec requirement… Read more »

Practical Rifleman
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Practical Rifleman

I am most certainly not under the assumption that mil-spec is synonymous with the best, if it were then m855 out of 14.5 inch barrels would not be a thing. But it is the benchmark that sets the standards. I am saying that when people make a claim that one part is better than another, they need to clarify what they consider better. In terms of durability and reliability, there are very many $600 ARs out there that are on par with the $2000 ones. In terms of under 2 MOA accuracy, special features, exotic metals and redesigned parts, perhaps… Read more »

David, PPT Editor
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I think it depends on how you measure what is “better” then. If you’re limiting the definition to durability and reliability in pure mechanical terms, then most ARs over around the $600-800 price point are not “better” and if they are it is only by slight amounts. However, I wouldn’t limit the definition like that. Accuracy, features such as ambi controls, exotic metals/hybrid metals/use of polymers to if not increase durability or reliability then to maintain the same levels but with reduced weight, smoother operating parts such as an improved charging handle or trigger, and adjustable gas blocks to allow… Read more »

Practical Rifleman
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Practical Rifleman

Exactly. I agree 100%. All I ask of authors is that when they say something is better, they state why. By not stating that a certain part is better in terms of a particular feature or upgraded material, it creates a feeling that only expensive parts are good. Everyone wants the best, but if professionalls never actually quantify what is better about a certain selection, the best becomes the most expensive, instead of uniquely tuned to an individual. While I agree that good, better, best should not be only in terms of reliability and durability, reliability and durability are typically… Read more »

Daddy
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Daddy

Six months late here but… “in reality what is better is ergonomics, decreased muzzle flip, lighter weight, better materials etc. All of which is better only in certain instances” Since your concern is that the author be extremely specific, I’d only ask the same of you. Got any certain instances when increased muzzle flip would be better? Because in that quote you implied there are such instances. Also, in your sentence fragment beginning with “All of which is better…” you meant to use the word “are” instead of “is” and you also forgot the last comma in the list before… Read more »

Practical Rifleman
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Practical Rifleman

First of all, thank God there are people like you who act as self appointed internet grammar police. I sleep so much better at night knowing that somewhere out there, there are people ensuring our great language is not corrupted by the subtle errors one might make while posting on a blog. Second, I do not feel that the section that you quoted out if context suggests in anyway that an increase in muzzle flip is beneficial. Decreasing the muzzle flip of an AR is not always a priority to a shooter, therefore installing any type of brake would serve… Read more »

Jay
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Jay

I have assembled many AR style rifles. I have gone the rout of milling out my own lowers and buying stripped. He pretty much states his criteria at the beginning. I can see you taking issue with “durability” but have to agree when it comes to the quality of the machining. Its noticeable between brands. I just bought a aero precision M5 lower 2 weeks ago and have to agree with author. The machining and finish are top notch. There is nothing inherently “better” per say but i did get a better fit, finish, and machining than others i own.… Read more »

XRey
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XRey

First, great article. I’ve been in the market for an AR style rifle, but am not a fan of the .223. I used to hunt deer in South Texas, the preferred gun was a Remington 700 .243. Never saw a need for a semi-auto since it was always one shot, one buck. Sold the .243 years ago and am now looking for a hunting caliber AR, not to hunt, just to have. I want an AR, I don’t need an AR. When I was hunting, I’d go to the range, take 2 shots to verify the rifle was sighted, then… Read more »