Buying an AR-10 is easy, but grabbing one off the shelf can’t deliver that satisfying feeling of knowing you built your own rifle.
Picking out an AR-10 lower can be a little daunting, but hopefully, by the end of this read, you’ll be able to confidently go out and choose the lower that is right for you!
I know a lot of people 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 rewarding.
Like me, I also know 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.
THE QUICK LIST
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Editor’s Pick
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Best High Tier Lower
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Best Bang for Your Buck
Table of Contents
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It’s Just Plug and Play, Right?
Unlike AR-15 Lowers, not everybody with a CNC machine or every major company makes AR-10 lowers. Additionally, the AR-10 was never adopted into military service — so what does that mean for you?
It means that there is no true standardized pattern for the AR-10 — so there’s no such thing as “mil-spec” and you need to be aware of the compatibility when buying uppers and lowers.
There are two primary patterns of AR-10 lowers — DPMS and Armalite. DPMS receivers feature a rounded cut near the rear of the receiver, whereas the Armalite uses a slant cut.
While these are the two most common patterns, with the DPMS being the most widely adopted, other proprietary lowers exist, so be sure to read each manufacturer’s description carefully.
What To Look For
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 competent and properly licensed should be able to turn out a functional AR-10 lower.
You can even buy 80% lowers without going through a dealer and finish the machining yourself at home with nothing fancier than a jig and a drill.
I typically look for forged or billet lowers. I’ve never found cast or polymer lowers to be as nice as the other two options, not to mention they are typically weaker. 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.
Aside from the materials, you will want to make sure you are getting all the features you may want. Comforts like ambidextrous controls, flared magwells, and match triggers may be worth a look — but beware, as the cost of what you want can add up quickly.
So, if you’re looking to build an AR-10 from scratch, or at least build a complete lower, here are some lowers to take a look at.
Best AR-10 Lowers
1. Aero Precision M5 Lower
I have made no secret that I love Aero Precision’s stuff. I’ve used their uppers, lowers, bolt carrier groups, and handguards extensively, and the only complaint I have is that I sliced my finger on a random staple on one of their packages once.
The Aero M5 Lower features an integral trigger guard for strength and a flared magwell. It also has a polymer tension screw that lets you adjust the fit of your upper and lower to eliminate wobble.
The Aero M5 utilizes the DPMS pattern and works with easy-to-find AR 308 parts and mags, giving you plenty of aftermarket options to cover all of your needs.
I’ve never once had an issue with an Aero Precision product, and I have two rifles with almost 5,000 rounds each through them.
For someone like me with lots of access to lots of guns, it’s rare to have guns that I come back to over and over. My Glock 19 and two Aero competition guns have been the exception to this rule.
At $119, the Aero M5 lower is an excellent value from a company with a well-earned reputation.
Prices accurate at time of writing
Prices accurate at time of writing
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25% off all OAKLEY products - OAKLEY25
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What do you think of this Aero lower? Let us know by rating it below.
2. Seekins Precision SP10 .308 Receiver Set
When you build rifles, 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 will allow you to get a perfectly mated and matched upper, lower, and handguard all at once.
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.
Seekins is one of the top manufacturers in the industry. Glen Seekins and his company have been making great rifles and parts for many 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.
I will say 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 minimum fitment issues.
Of course, these issues can be eliminated entirely if you buy all your major parts at the same place.
Also, if you’re reading this and suddenly jonesing for a completed rifle, worry not! You can buy a completed rifle made with all Seekins parts where available, and the fit and finish are as good as any in the industry.
Prices accurate at time of writing
Prices accurate at time of writing
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25% off all OAKLEY products - OAKLEY25
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3. LMT .308 MARS-H Stripped Lower Reciever
If you already know you want to throw down some serious cash for a serious rifle, look no further than the LMT .308 MARS-H lower receiver.
LMT has a long history of extreme attention to detail, top-notch quality control, and innovation, which have netted them military contracts over the years.
Aside from the outstanding build quality, the MARS-H stripped lower is fully ambidextrous, setting it apart from the other lowers on this list.
This means you get an ambi bolt catch, mag release, and safety selector already installed. Just add the trigger and stock components of your choice, and you are in business.
While the LMT is one of the undisputed best AR-10 lowers on the market, it does come with a few caveats…
LMT only guarantees the fit of their own uppers on their lowers. Other uppers may fit and function, but you will need to check before mixing and matching.
Fitment aside, the other thing about the MARS-H is the price. With the stripped lower coming in at around $485, it is one of the more expensive options on the market.
That said, you get what you pay for, and this bad boy is truly operator tier.
Prices accurate at time of writing
Prices accurate at time of writing
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25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
4. PSA GEN 3 PA10 Complete MOE EPT Lower
If you want a solid, functional lower at a great price, Palmetto State Armory is your huckleberry.
We’ve reviewed their PA-10 in both .308 Winchester and 6.5 Creedmoor, which were amazing rifles for the money.
In general, PSA is a fantastic place to look for affordable guns and parts in general (I think they have some black magic voodoo involved in their low prices).
Despite the low cost, PSA’s in-house brand is perfectly serviceable and totally adequate; you just lose out on some of the bells and whistles of more expensive brands.
Oh, and did I mention it’s a complete lower? That means Magpul stock, overmolded grip, integral trigger guard, PSA’s enhanced polished trigger — the whole deal. And it is all yours for about $240.
Even in its completed state, it’s still cheaper than many stripped lowers on the market and certainly cheaper when you compare the prices of other completed lowers.
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, or will it beat out a $2,500 build? No.
Will it go bang every time and still get you solid accuracy? Absolutely.
Prices accurate at time of writing
Prices accurate at time of writing
-
25% off all OAKLEY products - OAKLEY25
Copied! Visit Merchant
Although there are reports of successfully mixing different uppers and lowers, PSA technically uses a proprietary pattern, so sticking to PSA uppers might be your best bet.
With extremely budget-minded pricing, you can even conceivably snag both a .308 and a shiny new 6.5 Creedmoor version — for around the price of a single rifle from another manufacturer.
Final Thoughts
Hopefully, this helps you in your quest to find the perfect lower for your next build.
Looking for other parts for your build? Check out our review of the best AR-10 barrels! Want to skip the build process altogether? Check out our list of the best complete AR-10 rifles!
18 Leave a Reply
I want to build a ar 220 swift anybody help me out? Not sure where to start.
Aero has never steered me wrong. One of my favorite rifles in .308 Seekins is the backup plan till my pimp hand is strong. Then you can graduate then you can upgrade to LMT
A friend told me today that AR10 lowers aren't standardized like the AR15's.
And not all uppers will fit all lowers. Is this true.
YES!!! AR-10 and LR308 (DPMS Pattern) are not the same. If you look in this article at the AR-10 lower, notice how the cut in the back of the receiver, near where buffer tube attaches, is cut at a 45 degree angle, as opposed to the others which have a curve into a 90 degree buffer tube adapter. AR-10 and LR308 do not mix. Make sure you are paying attention when purchasing parts to build guns!
Armalite makes an ar-10a that’s takes DPMS style mags the ar-10b takes Armalite only mags. Also love aero precision built several rifles with there parts I think there top notch! I think the palmetto ar-10 has some proprietary parts you can only use there uppers I try to stay away from that.
Any ideas where you can purchase AR10 308cal Strip lowers with Custom Serial Number and 100% ready to put together?
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!
On my bushmaster ar 10 I can't take ar 15 take down pins the have a bit of wiggle and have had no luck in getting them to work waiting for the new one to come in now any day hopefully
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 requirement. Therefore it cannot actually exceed mil-spec requirements, because it has never actually met them. Technically, by being a Billet receiver, it is actually weaker than the mil-spec forged lower whose specs they claim it exceeds.
Does it look cooler? Yes. Does it have an ambidextrous bolt release? Yes. Does it have a built in Tension screw? Yes. Does it cost more and have a SP symbol stamped on the side? yes and yes.
But none of these things make it better than forged mil-spec lower. Not in the sense that it will fail in operation, or break under stress.
Arguably, there are parts that are better than a mil-spec part, depending on purpose. I am looking at you, SS .223 Wylde barrels. But they are "better" in the sense that you may be able to squeeze additional accuracy out of them, which is definitely a step up from a normal 4140 PSA barrel. But since neither of them are made of the mil-spec required 4150, there is no need to suppose that either are better than the Mil-spec barrel in terms of durability.
After-market triggers can greatly improve firearm control as well, but this is not directly comparable to mil-spec as mil-spec trigger groups are largely unavailable to civilians.
So I am not saying that you should just run out and buy the cheapest stuff you can find, but there needs to be some quantifiable performance increases between two components before you can claim that one is better than another.
If one component has "features" that are worth the extra money to you, such as the Ambi bolt releases and tension screws, then yes, that receiver is better for you, but not necessarily better than a normal receiver when the mil-spec requirements are being used as the judgement bar.
Great article though, I enjoyed it.
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 is honestly just a bad barrel. It works, it works good enough for most combat applications, but it is still a very cheap and low tier barrel.
Cost is often about features and name brand, but there is also a material and manufacturing component.
If all you want is a rifle that works - then there is nothing wrong with budget brands that don't offer any fluff - such as PSA, a great budget option.
If you want more from your rifle, features, accuracy, wider application, comfort, improved materials, etc. it is going to come at a cost.
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 not so much.
When someone makes a claim, they need to provide a reason.
For example, I am a left handed shooter. For me the best AR upper assembly would ideally eject to the left, this is what makes it the best for me. It will usually cost more to have this feature, but that additional cost has zero effect on the performance of the firearm itself, and therefore is not inherently better, because it is a feature.
Now having a titanium cam pin for my bolt would be a direct upgrade to the gun, vastly reducing the chance of a critical part failure. This is something that is better, not because of personal preference, but because of straight up better materials.
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 for a wider use of ammo/situations would all - in my definition - make for a "better" rifle.
Even, as you mentioned, would having a rifle that ejected to the side that was more useful to me. Comfort is a major part of what makes a good rifle good or not.
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 the first and foremost mentioned attributes in the description text of an AR, occasionally with claims of accuracy.
So when a claim is made that x is better than y without definition, it is easy to assume that x is inferior in terms of reliability and durability, when in reality what is better is ergonomics, decreased muzzle flip, lighter weight, better materials etc.
All of which is better only in certain instances.
Pencil barrels are better for people wanting to build a lightweight gun, but worse for a person wanting to shoot distance.
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 "etc."
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 no purpose for them.
That does not mean that it would not work as designed, it means that the user may not need it.
However, if the shooter does want some type of recoil or muzzle flip reduction, a brake would be a direct upgrade over something such as a crowned barrel. That would be better for them, but at a cost of noise and muzzle blast.
If a person makes a recommendation for a specific component, based on various features the component has, I would expect that they would state those features, instead of just claiming that's it's better.
Also, since you took the liberty of correcting some of my punctuation and grammar, and no doubt will continue to do so, I would like to point out a relatively minor infraction of your own.
Starting a sentence with a past participle and no pronoun creates a confusing sentence. "Got any" is better written as "do you have any".
But hey, you do you, dude.
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. Makes the forged 80 percenters i got look like they were forged using child labor and my other stripped lowers look cheap. lol. That set screw for fit is a HUGE plus as well.
The main reason they are better than mil-spec is their tolerances. Plus,
mil spec is generally not specific.
It’s a set of specs the military puts out a bid on. They are happy to receive guns or parts that exceed military specifications. But they’re not necessarily gonna pay for them.
So it is very possible to have a milled upper than surpasses mil-specs.
In most cases. Mil-spec is a base line of specifications that must be met or exceeded. So parts can be different in many ways and still be mil-spec or better than mil-spec
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 one shot for a nice buck, so 20 bullets would last 7 years. I'm not into shooting hundreds of rounds to test my skill at hitting paper tigers. Same reason I don't golf, I'm not into hitting a ball with a stick, chasing the ball, then trying to get it into a hole. I have better things to do with my time.
Now back to the article and your comment on the PSA ""If you’re a quantity over quality person, this is definitely the route to go."
Whether it's motorcycles, cars, computers, steaks, etc., it's about bang for the buck, no pun intended. What's the best product you can buy for the money? I like to build things, I've built an airplane, but sometimes the better path is off the shelf.
I've looked at PSA, the Gen2 PA10 is currently $599, that's a deal. Also on the list, the DPMS Oracle. There will be other deals, the gun industry is getting spanked. Buy low.