It has been said the AR-15 is âAmericaâs Rifleâ and I would tend to agree! But sometimes, you just need more power than what you can fit in an AR-15. Enter, the OG, the GOAT, the AR-10.
Designed in the mid to late 1950s, the AR-10 never really got to reach its full potential until the 2000s. While it was always a great platform, it has only recently really reached the hands of the mass market.
If you want to build one of your own (and I recommend you do since itâs fun!) then one of the first things youâll need is a lower.
From the cheapest to the best, we have our top recommendations for the Best AR-10 Lower!
Best Budget Buy
|PSA PA-10 Gen 3 Stripped Lower|| ||$150 Shop NowClick to read my review|
|Aero Precision M5 Stripped Lower|| ||$205 Shop NowClick to read my review|
|LMT MARS-H Stripped Lower|| ||$540 Shop NowClick to read my review|
|Rainier Arms Ultramatch MOD3 Receiver Set|| ||$575 Shop NowClick to read my review|
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What Makes Lowers Different From Each Other?
For the most part when it comes to the AR-15 and AR-10 — a lower is a lower.
Durability, reliability, and compatibility should effectively be equal across any lower that you buy. From the ultra bargain basement to the insanely high-end, there simply isnât a lot of difference from a fundamental standpoint.
What does set them apart from each other is the controls, fit and finish, and just how nice they look.
The biggest of those is the controls. While the basic mil-spec controls will be basically the same, higher-end lowers are far more likely to have extras like ambidextrous safety, magazine release, and bolt catch.
Some lower only have ambi safeties, some will have bolt catch designed to be ambi release but not ambi hold open, while others will have all of them together.
Fit and finish can be subjective and technically speaking fit is mechanically unimportant since mil-spec actually allows for daylight between the upper and lowerâ¦ weird, right?
But getting a nicer fit and finish can make a huge difference in how your rifle looks. And looking good is half the battle!
All of that said — donât base your decision on what you think will be the most reliable, because the truth is they simply wonât be any different. The lower in an AR-15/AR-10 just isnât important for that.
A good trigger inside of your lower is all you need.
7075-T6 Vs. 6061-T6 Aluminum
A lot of people try to make a big deal out of 7075-T6 and 6061-T6 aluminum since these are the two most common types of aluminum to be used in firearms.
But the fact is when it comes to your lowerâ¦ it just doesnât matter. Like, at all.
Speaking metallurgically, these two types of aluminum are very similar but 7075-T6 is quantifiably stronger. Depending on your application, this can be important.
But in the context of making a lower out of it, the extra strength wonât do you any good.
Technically, 7075-T6 is almost twice the strength with a yield of ~73,000 PSI where 6065-T6 only has ~40,000 PSI.
The thing isâ¦ youâll basically never encounter something that wonât break a 7075-T6 lower, but will break a 6065-T6 lower.
Any falls, drops, or banging around is going to be way, way under 40k PSI. But anything catastrophic like your lower being shot will be well over 73k PSI.
All of that said — there is nothing wrong with 7075-T6 aluminum and there is no reason to not get it if it is available. It might cost slightly more, but normally not by much. Also, most of the better manufacturers will already use it and wonât even offer a lower-tier line.
But I would never base my decision on it. Controls, fit, and finish, and my lower being compatible with my upper is what I care about.
One of the best features of the AR-15 is how standardized it is. Take basically any lower, slap basically any upper on it, and youâre good to go. You never have to worry about it fitting together.
The AR-10 isnât like that.
While the AR-15 became a standardized firearm due to massive military adoption, the AR-10 never really did. Sure, it was picked up in small numbers outside of the USA but that is nothing like the AR-15 and M16.
Because there is almost no true standardization in the AR-10 family, many manufacturers’ lower receivers will only work with their uppers. You canât mix and match as freely.
I therefore strongly recommend that whatever lower you get, you go with an upper from the same company.
Preferably, a complete upper that includes handguard, BCG, and barrel.
The bare minimum though would be a stripped upper receiver. If you go this route, make sure you look at what handguards and BCGs are known to be compatible.
Best AR-10 Lowers
1. Palmetto State Armory PA-10
If you want a bargain, Palmetto State Armory is impossible to beat with their PA-10 line of AR-10 style rifles! You can grab a blem stripped lower for only $99 and a complete lower for around $320 — that is a crazy good deal in AR-10 land.
These are also quality rifles, far better than their price would make you think. The PA-10 Gen 3 has had a lot of improvements over the years and is a workhorse of a rifle.
They even use 7075 aluminum!
The 6.5 Creedmoor version Iâve seen shot accurately to 1 mile and Iâve personally shot mine to 700 yards without breaking a sweat.
The finish isnât as nice as it could be, but the fitment is awesome.
One downside though is that the PA-10 can only be used with a PA-10 upper and handguard. You get some flexibility when it comes to BCGs, but the stripped upper and handguard need to be from PSA.
Even with this limitation, this is an awesome rifle for a great price.
2. Aero Precision M5
My personal AR-10 is an Aero M5 that I built using one of their âBuilder Setsâ. The Builder Set comes with a stripped lower, stripped upper, and a handguard. Add your own barrel, BCG, stock, and LPK and youâre in business.
I built mine in 6.5 Creedmoor and have shot it to over 800 yards with awesome results.
Value for your dollar, the Aero Precision is in a class of its own. The fit and finish is wonderful, the parts are well made, and they also use 7075 aluminum.
No awesome features to point out or major contracts that Aero Precision has won, they just make a great rifle and are proud of it.
If I was picking just one to recommend to you — the Aero Precision M5 would be my go-to choice for hunting, SHTF, plinking, or anything else general purpose.
3. Lewis Machine & Tool Company
Get ready for some wallet shock — the LMT MARS-H stripped lower is over $500.
And reallyâ¦ It’s totally worth it. If youâre willing to spend the rest of the money to finish the rifle.
The MARS-H is LMTâs top-tier lower with full ambi controls. This is also one of those ultra-rare truly combat-proven platforms with real-world adoption and uses to back it up.
The British Army adopted the MARS-H as the L129A1, as did the Estonia Defense Force.
While expensive, if you really want the best — this is it.
Fully ambi controls are also a really nice touch. The safety, bolt catch/release, and magazine release are all usable from either side of the lower. Perfect for the wrong-handed among us but a real boon for the rest of us also.
If I was going to pick one AR-10 style rifle to trust my life to at the end of the world, the MARS-H would be my first pick.
4. Rainier Arms Ultramatch
Hard to find in stock, but totally worth it if you can. Rainier Arms Ultramatch is a great line of equipment that is often overlooked by many people.
First off, this is a stripped upper and lower set. That helps take some of the stings out of the price at least.
This is also just a sexy-looking set, the aesthetic design Rainier has put into their AR-10 design is clean and refreshing.
Coming standard with an ambi magazine release and bolt release, this is a step above most lowers but not as fully accessible as the LMT offering.
Something I really like is that there is no forward assist! If youâre part of the no-FA fan club, this will be a nice addition that can be hard to find in other formats.
A great lower is the perfect starting point for your next AR-10 build!
My personal favorite is the Aero Precision M5 Stripped Lower but there are lots of options on the market.
Find what fits your budget, gives you the features you want, and pleases your eye and youâll be set for a great large-caliber AR.