Best AR-15 & AR-10 Lower Parts Kits (LPK)

Finishing up your AR-15 build and need a lower parts kit to finish out that stripped lower?

Building your own isn't just a fun hobby. You can typically build an AR-15 that will perform better than a pre-built that costs 30-50% more.

Taking matters into your own hands also lets you pick the exact parts you want without paying for the ones you don’t.

To turn that lower into the beginnings of a rifle or pistol, you’re going to need a lower parts kit

We'll cover what's in a standard AR-15 lower parts kit and share our favorite picks, plus some AR-10 kits since there are some differences.

How We Tested the Best AR-15 Lower Parts Kit

This article is a meta-analysis based on our experience with parts kits over the years at Pew Pew Tactical. We polled the editors and writers to see their top LPKs that blend value and features and developed our list based on those favorites.

These are the lower parts kits we keep coming back to build after build.

Best AR-15 Lower Parts Kits

1. BCM Lower Parts Kit - Editor's Pick LPK

Editor's Pick LPK

BCM Enhanced LPK

$119

at BCM

Prices accurate at time of writing

$119 at BCM

Brownells (see price)

Primary Arms (see price)

We love complete BCM rifles and uppers.

And this lower parts kit has become our go-to for new lower builds.

If you know you already want a comfier grip and slicker trigger, the BCM kit comes with their nice Mod 3 grip and nickel boron coated trigger.

Plus if your lower is mil-spec and needs a trigger guard...it's in there too.

If you want the barebones stuff...they have a commercial kit too.

BCM LPK

$119

at BCM

Prices accurate at time of writing

$119 at BCM

2. CMMG AR-15 Lower Parts Kit - Best For Beginners

Best For Beginners

CMMG AR-15 Lower Parts Kit

$58

at Palmetto State Armory

Prices accurate at time of writing

$58 at Palmetto State Armory

Brownells (see price)

CMMG (see price)

Primary Arms (see price)

CMMG makes great AR-15 carbines and pistols. This kit is a solid starting point to build one of your own, and we love how user-friendly it is.

This kit comes with color-coded bags with a legend on the back of the box to tell you specifically what's there. You can't mess it up!

Is this kit full of bells and whistles? No. But it has everything you need and is put together with the customer in mind.

We highly recommend this CMMG LPK for a first-time builder who isn't looking to upgrade their trigger and pistol grip just yet.

3. Palmetto State Armory - Best Affordable LPK

Best Affordable LPK

Palmetto State Armory MOE Lower Parts Kit

$59

at Palmetto State Armory

Prices accurate at time of writing

$59 at Palmetto State Armory

Palmetto State Armory might sell the most AR-15s in the country.

They're one of my go-to sources for anything AR-15. I've built plenty of their lowers with their LPKs. Check out all our reviews of their guns here.

It may not look like much but those little baggies are a lifesaver. They organize parts into areas of lower assembly so you don't have to guess which spring or detent is which.

And almost all their kits come with additional furniture. I like that they throw in a Magpul MOE grip for this kit since I would have added one anyway.

Most lower parts kits don't come with buffer tube assemblies. If you want to buy everything at once, get a Palmetto State Armory Magpul MOE complete lower build kit.

Check out the entire selection of build kits and LPKs from Palmetto State Armory. Some come with an upgraded EPT trigger that's nickel-boron coated for a better trigger feel.

What's your take on the Palmetto State Armory lower parts kit? Give it a rating below!

4. Aero Precision Lower Parts Kit - Best Minimalist Lower Parts Kit

Best Minimalist LPK

Aero Precision LPK Minus FCG/Trigger Guard/Pistol Grip

$39

at AR15 Discounts

Prices accurate at time of writing

$39 at AR15 Discounts

Primary Arms (see price)

Looking for something no-frills when you already have everything else, like the trigger and pistol grip?

This Aero Precision lower parts kit gets the job done at an affordable price.

They've also done well in my Aero Precision, Anderson Manufacturing, and Palmetto State Armory lower receiver builds.

Looking for a more standard lower parts kit with a trigger and A2-style pistol grip? Aero Precision has that, too.

5. Geissele AR-15 Lower Parts Kit - Best Mid-Tier

Best Mid-Tier

Geissele AR-15 Lower Parts Kit

$0

at

Prices accurate at time of writing

$0 at

Speaking of Geissele...they are known mostly for their triggers, muzzle devices, and handguards, but they make everything from complete rifles to parts kits as well.

And the Geissele parts kit is pretty great.

It’s precision-machined with all the skill and accuracy you’d expect from Geissele, and the price isn’t half bad for a set this nice. The only things that are missing are the pistol grip and trigger group.

I’d personally recommend throwing your favorite grip on there and coupling that with a matching Geissele SSA-E trigger or some other equally awesome Geissele offering.

Now, let's move on to the AR-15's big brother, the AR-10.

Best AR-10 Lower Parts Kits

Most AR-15 lower parts kit components will work with an AR-10 but, since the AR-10 is shooting larger cartridges like 7.62 NATO and 6.5 Creedmoor, the receiver and magazines are much larger. They're also stronger to handle the increased recoil.

Because of that, these parts are not interchangeable.

• Bolt catch and roll pin
• Pivot/takedown pins
• Buffer and spring
• Magazine Catch

There are also two patterns of AR-10 lower receivers. The most common by far is the DPMS variant. Unless yours says it is the Armalite style, chances are it's DPMS.

6. Palmetto State Armory PSA10 MOE EPT Lower Parts kit - Best AR-10 Kit

Palmetto State Armory's AR-10 is proprietary and works great (full review here), but their lower parts kits work with any DPMS-pattern AR-10s from other manufacturers.

Best AR-10 Kit

Palmetto State Armory PA10 MOE EPT Lower Build Kit

$150

at Palmetto State Armory

Prices accurate at time of writing

$150 at Palmetto State Armory

MIRA Safety (see price)

Ammunition Depot (see price)

Rainier Arms (see price)

Show all prices

This complete kit includes the buffer assembly, a collapsible stock, and an upgraded pistol grip -- all from the Magpul MOE family.

More importantly, it gets an upgraded Enhanced Polished Trigger that's a little nicer than the mil-spec triggers that come with most kits. It's no match trigger, but it's a step in the right direction and a great value.

Palmetto State Armory also has tons of other packages with different triggers and grips.

7. CMMG AR-10 Lower Parts Kit - Best Budget AR-10 Kit

Best Budget AR-10 Kit

CMMG AR-10 Lower Parts Kit

$67

at Primary Arms

Prices accurate at time of writing

$67 at Primary Arms

CMMG (see price)

Palmetto State Armory (see price)

OpticsPlanet (see price)

Consistent with our AR-15 recommendations, we like CMMG's AR-10 lower parts kit because it's a great value and super intuitive to assemble. 

My first AR-10 lower used one, and it worked fine.

You might want to swap out the A2-style grip and mil-spec trigger down the road but this will give you a great platform to start shooting and find out what you care to upgrade and what's fine as-is.

What If You Lose Parts?

Before you get started on your first AR build, just know that eventually you're going to send a tiny spring or detent into orbit, never to be found. It happens to all of us. Fortunately, you don't have to buy a whole new lower parts kit to replace it.

NBS AR-15 Oops! Kit - Best Spare Parts Kit

Best Spare Parts Kit

NBS AR-15 Oops! Kit

$7

at AR15 Discounts

Prices accurate at time of writing

$7 at AR15 Discounts

Primary Arms (see price)

OpticsPlanet (see price)

This replacement parts kit gives you a spare of all the little springs and other fiddly parts you’re likely to lose, as well as spares for when springs start to wear out and break down.

What's in a Lower Parts Kit?

A complete AR-15 or AR-10 lower receiver contains the following components:

• Trigger, spring, and pin
• Hammer, spring, and pin
• Disconnector and spring
• Bolt catch, plunger, spring, and roll pin
• Safety selector, detent and spring
• Takedown/pivot pins, detents and springs
• Buffer retainer and spring
• Magazine catch assembly
• Trigger guard assembly
• Pistol grip

I can feel our eyes glazing over when confronted with that parts list but remain calm. I promise it's easier than it looks.

If you can hammer a nail and turn a wrench, you’ve got what it takes to build a lower of your very own.

Upgrading From Standard Parts

Finally, I want to make a note about upgrading these parts kits. A spring is (usually) a spring, but an upgraded trigger, buffer, grip, and stock can really make a huge difference in how your rifle or pistol performs.

The trigger is really going to be the single biggest performance factor for the speed and accuracy of your gun.

If you want to upgrade your build right from the beginning, these are the Best Drop-in AR-15 Triggers.

After that, pick out your furniture. Bravo Company or Magpul, in whatever color and design you like, and at whatever price point matches your build goal. 

See our favorites in Best AR-15 Furniture.

Final Thoughts

That does it for lower parts kits. You should now know what to look for, how to choose a lower parts kit, and what to buy, as well as how to move on from the standard parts kits.

If you’re building a rifle, and you’ve got your lower, this should get you the rest of the way to completing it.

Building a rifle? Let me know what parts kits you prefer in the comments below! For more AR-15 accessories, check out our Best AR-15 Upgrades: Triggers, Brakes, Handguards, & More.

Latest Updates

August 15, 2024: Added in BCM Enhanced LPK.

May 28, 2024: Added more detailed product information and updated supporting content.