Best AR-10 Build Kits – 2021 Complete Review

| Last Updated: August 25, 2021

Predecessor of the AR-15, the AR-10 is an excellent option for shooters and hunters who want to fire powerful center-fire cartridges from their semi-auto rifles.

It is a common misconception that the AR-10 emerged after the AR-15, but it is actually the other way around. An AR-10 build kit is a great option for hands-on firearm enthusiasts.

Scroll down to see some of the best AR-10 build kits available today.

Comparison Chart of the Best AR-10 Build Kits

  • Includes a Lower Receiver
  • Includes Springs, Pins, and Detents
  • Magpul Buttstock Made from Polymer
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  • Magazine Catch Assembly Included
  • Includes Trigger Assembly With Pins and Springs
  • Includes a 6-Stage Buffer Tube for Better Stock Adjustments
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  • Best .308 Build Kit for an AR-10
  • Includes Buttstock and Buffer Tube
  • Includes All Your Springs, Pins, and Detents
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What to Watch For When Buying an AR-10 Build Kit

There are a few things to keep an eye out for when you start your search for the best AR-10 build kit for your needs and purposes. The word “kit” can be a little misleading as to what is included and there are certain factors to look into before making your final decision. Use the following tips and info to make your shopping experience a smooth one.

This Section Written By: Brian Belko

Expert Author

Brian Belko: Gunmann Author

Brian is an experienced freelance writer and technical writer who has previously written for publications such as Wide Open Spaces, Bigfoot Gun Belts, Alien Gear Holsters, and Kampgrounds of America. He brings both a passion for writing and a love of the outdoors to his published content.

Aside from writing and the outdoors, Brian enjoys gardening, being a co-host on The Nostalgia Blast Podcast, and learning to code.

Centerfire Needs

The 5.56x45mm NATO round that is predominant amongst AR-15s is considered to be an intermediate round. It is best used at ranges under 500 yards, it simply doesn’t have the same range and power potential as a larger centerfire cartridge such as the .308 Winchester or the very popular 6.5 Creedmoor. These larger centerfire cartridges are ideal for longer-range shooting and big game hunting, easily reaching out to 800 yards and beyond.

The direction you go largely depends on your personal needs and the tasks you need your gun to accomplish. This isn’t to say that you shouldn’t consider adding an AR-10 to your arsenal or collection if you aren’t shooting at extreme ranges or hunting big game. They are a great shooting platform. It is just good to understand a gun’s capabilities before making a final decision.

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Size Matters

Keep in mind that the AR-10 is a larger and heavier weapon than the AR-15 platform. They might look similar in design and overall shape, but don’t be fooled. Be ready to shoulder the weight if you do go with an AR-10. This means investing in a good sling and bipod if you plan to do some hunting or even if you just have a long walk from your vehicle to your shooting range.

What’s in a Kit?

As was mentioned earlier, the word “kit” can be a little misleading. Not every AR-10 build kit includes the same parts or the same type of parts. This is where an eye for detail really comes in handy. Pay close attention to the parts list so that you understand exactly what you are getting in the build kit you choose. Some kits only have upper parts, some only have lower parts, and some include everything for an entire AR-10.

You’ll also have a choice in the level of work that a kit takes to be completed. The level you go with will depend on the type of gunsmithing experience you have. Pre-assembled kits are easy for almost anyone to put together. Drop-in kits are more involved, but won’t require any help from a professional gunsmith. There are also kits even more involved available for those who really want a challenge or in-depth project. It all depends on what you want and your skill level.

Review of the Best AR-10 Build Kits

Below are five of the best AR-10 build kits currently on the market. As you look through each of these, it is important that you read through them carefully. You may find that it will include a part or two that you might need.

Plus, you’ll need to know what’s included in each kit so you don’t have to go after a specific part and purchase it separately. With that in mind, let’s dive into the first AR-10 build kit starting with the “best overall” kit currently on the market:

Best Overall

PSA MOE ACS-L EPT Lower Build Kit

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Next, we’ll be taking a look at another PSA brand kit. This time, we’ll be looking at a lower build kit. This includes the lower receiver and the parts that will make this part of your AR-10 rifle fully functional.

Included in this kit is your buttstock, which is made from polymer and is proven to be quite durable. Also included are your pistol grip, tubes, springs, pins, and detents. Everything is here to make sure that your lower half is fully functional and has the ability to fire each and every round you put through it.

The trigger is perhaps the star of this ensemble. It has a crisp, smooth pull that blows all the other triggers out of the water. Yes, even the mil-spec triggers. In fact, this trigger is a lot smoother than a standard mil-spec trigger.

If getting off shots as quickly and smoothly as possible is something you want, this lower build kit will probably be your best investment yet.

The parts are easy to assemble and install. So you’ll spend minutes to even a couple of hours putting these parts together. Before you know it, you’ll be able to finish your AR-10 rifle project in a record amount of time. If it’s your first time building an AR-10, then it might take a little longer.

Regardless, hard work and taking your time will pay off once you complete it and take it out for a test drive at the range.

If you’re looking for the complete package in the lower receiver department, this PSA product just might be the answer you’re looking for.

Bottom Line

This lower kit is perhaps the best kit to invest in if you’re a first-time AR-10 buyer. Consider this a possible starter kit. At the same time, it’s better to start it piece by piece than having the whole kit and kaboodle. However, if you’re up for the challenge, then a full-on kit like our previous PSA kit might be worth the investment too.

However, if you’re taking things little by little, then a product like this might be a good place to start. If you’re looking for a high-quality set that will work smoothly and without any malfunction, this PSA kit will probably be the best possible option for you.


Parts and Accessories Were High in Quality

An Excellent Starter Kit for a First Time Builder

Most of the Parts Fit Perfectly Without Any Issues


Takedown Pins May Be Hard to Remove

Best 6.5 Creedmoor Build Kit

PSA PA-10 Classic Lower Build Kit

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The 6.5 Creedmoor is a long-range AR-10 rifle that has taken the gun world by storm. And it’s a force to be reckoned with, especially when it has the ability to hit targets from 500 to even 1000 plus yards out. It’s a rifle worth giving a try.

However, if you’re one of the many building Creedmoor rifles from the ground up, you’re obviously going to need a product that will make that puppy stand out. And of course, there’s a PSA kit for that.

More specifically, we’ll be taking a look at the PA-10 classic lower build kit. This kit is exclusively for the lower receiver of your AR-10 rifle. However, these parts are also compatible with rifles that fire Creedmoor cartridges. Included in this kit are your usual springs, pins, and detents. Also included is your trigger assembly.

This trigger will give you a crisp, clean pull each time you use it. Also included is a six-position adjustable buffer tube that will make the Creedmoor rifle adjustable and user-friendly for almost any shooter.

If you’re looking for the right parts to help make your AR-10 long-range beast the best of the best, you’ll need a compatible product. A lower kit complete with PA-10 parts will most likely work with Creedmoor rifles.

With that said, this PSA product is something that’s worth a closer look if you’re planning on building a rifle that is best used for any long-range application like hunting or competitive shooting.

Bottom Line

If you’re looking for a standard, classic lower parts kit for your AR-10 or your Creedmoor rifle build, then this PSA offering will probably be the best option for you. It has all the commonly found parts that make up a rifle’s lower receiver.

On top of that, they are high-quality parts designed to last you a long time. If you want a Creedmoor rifle that will be reliable for many years to come, then a kit like this will come in handy.


Easy to Install

High-Quality Parts

Fits Most AR-10 Rifles Perfectly



Best .308 Build Kit

CMMG Inc MK3 Gunbuilder’s Lower Parts .308 Kit

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For our last build kit, we’ll be looking at the best one for those who want or have a .308 caliber AR-10 rifle. We’ve decided to go with the CMMG Inc. MK3 Gunbuilder’s Lower Parts Kit.

The basic parts include the following: takedown pin (detent included), hammer and trigger pin, magazine catch, bolt catch (with spring included), magazine release, buffer retainer (with spring), and many more parts considered necessary for your AR-10 lower receiver.

All parts are made from high-quality materials and are designed to be durable and long lasting. This is a kit that will get your AR-10 rifle as close to mil-spec as possible. If you’re a fan of all things mil-spec, then you’re going to want to give this a closer look.

Bottom Line

If you’re more of a .308 caliber kind of shooter and want to build a rifle that will fire those types of cartridges, you’ll want a kit that will be compatible with your AR-10. The closest we can get to the best is the CMMG. All the parts for the rifle’s lower receiver are included and are definitely made to last.

If you’re looking to make your rifle reliable for as long as possible, all it takes is just the right parts to install. A product like this might be a good place to start.


Easy to Install

Parts are High in Quality and Craftsmanship is Excellent

Works With Most Uppers From the Aero Precision Brand


May Not Come With Assembly Instructions

One Reviewer Said That One of the Springs is Supposedly a Little Shorter in Length

One Reviewer Complained About the Magazine Release Button Not Being Long Enough

PSA Gen2 18″ .308 WIN 1:10 Rifle Kit

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The first kit we’ll be taking a look at is the PSA Gen2 18 inch .308 WIN 1:10 rifle kit. Of course, as the best overall, there is a reason we give it the honor. This is basically the total package in one kit.

Included are your lower and upper receivers, a barrel measured at 18 inches (with a 1:10 twist that’s best for lightweight ammo), the bolt carrier grip, and all the pins, springs, and detents that put it all together.

The receivers are made from high-quality aluminum, making a very durable rifle that will last you many years to come.

The barrel is made from stainless steel and is chambered in the .308 caliber. If you have some .308 rounds that are just waiting to be fired at the range or out in the field,  you’re going to need a rifle to fire off these rounds without any issues.

If you’re looking for a good AR-10 build kit that contains high-quality parts that allow for a reliable, fully functioning rifle that will work without any issues for years or possibly decades, then you have found it in the PSA Gen2 product You’ll have all the right parts in one kit and will never have to track down each part individually.

Bottom Line

Overall, it’s a pretty good kit for what’s included. And since it’s the best overall kit on the market, it surely lives up to the title. All parts are high in quality, the upper receiver is fully assembled, and everything you need is right in one kit.

That alone will save you time and a whole lot of money. If saving time and money is what you’re looking for in an AR-10 build kit, then the PSA might be exactly what you’re looking for.


Most of the Parts Fit Together Nicely Without Any Issues

Excellent for AR-10 Rifles Designed for Hunting Purposes

Will Save You a Lot of Money When Compared to Purchasing a Fully Built AR-10 Rifle


One Reviewer Had Complaints About Some of the Bolts Not Securing Properly

Some Users Have Had Fitting Issues With the Lower Receiver and the Corresponding Parts

PSA Gen2 PA10 18″ .308 WIN 1:10 15″ M-Lok ACS-L Rifle Kit

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Our next PSA product we’ll look at under the microscope is the best for those on a budget. If you’re looking for a product that won’t suck the life out of your bank account, then the PSA Gen2 M-LOK ACS-L Rifle Kit might be the one you’ll want.

So what’s included in this bad boy? First, this has an 18-inch barrel that is made from stainless steel and chambered in a .308 WIN caliber.

If you’re planning on building your AR-10 rifle into a force to be reckoned with, and in a caliber that is considered one of the most reliable in the AR-rifle family, then this might be the kit for you.

What else will you get from this? The barrel itself has a free-floating rail that will allow you to fully customize the upper receiver of your AR-10 rifle with any optic, scope, or other accessory you consider to be a must-use. The Picatinny rail will allow you to easily install your accessories without any issue.

Also included are your buffer tube, pistol grip, and buttstock. All are functional in their ability to allow you the best possible control over your rifle. These parts are also essential if you’re looking to reduce as much recoil as possible. Recoil can be the bane of any rifle’s accuracy ability.

If you hold accuracy to a high standard and want to reduce recoil, this product has the right parts to make sure it becomes a reality.

Best of all, this is affordable for most budgets. So needless to say, you get a heck of a lot more than what you pay for. No other budget setup will hold a candle to this PSA kit.

Bottom Line

As expected, this kit has exceeded the expectations of any budget shopper. You get all kinds of high-quality parts at a price you can afford.

Of course, we can agree that there should be an addition to this kit (like a magazine). Maybe they’ll update that in the not so distant future, but don’t quote us on that.

But right now, it’s still a pretty good option for those looking to get an AR-10 build kit worth the investment. If you want to get started on your AR-10 building project without the hassle of high prices, this product might be what you are looking for.


A High-Quality Kit at a Price That is Affordable for Most Budgets

Has the Ability to Shoot Accurate Shots From 200 to 300 Yards Out

An Excellent Starter Kit for Those Who Want a Challenge and Don’t Have a Lot of Money to Work With


Some Parts May Not Be as Tight of a Fit

One Reviewer Suggested That a Magazine Should Be Included

May Come With a Few Takedown Pins That Might Be the Wrong Fit

What’s in an AR-10 Build Kit?

Knowing what’s inside an AR-10 build kit is important. You’ll need the parts that will make your AR-10 rifle as fully functional as possible. Plus, having the necessary parts included is way better than having to track down each and every part separately. And that will mean paying more. With that in mind, here are some of the common parts found in most AR-10 build kits:

Upper and Lower Receivers

Most of your AR-10 build kits include both an upper and lower receiver. These are essential, along with the parts that come with it. Without one or the other, the rifle will obviously be rendered useless. Your upper receiver will include parts like the barrel, forends, handguards, and other parts.

Your lower receiver will most notably include a trigger assembly, magazines (including a mag catch), and other assemblies. If you have both receivers in a kit, then you’re pretty much off to a good start.

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Gas Block

Some AR-10 build kits will include complete gas kits. Some won’t. But one thing for sure is that a gas block will almost always be included in AR-10 build kits. Having a gas system that will help propel your rounds and expel them out of your gun is essential. Since you’re using an AR-10 rifle, most gas blocks will be part of a rifle gas system. If your kit does not include a gas tube, don’t fret. You can always buy one separately, even at affordable prices.


This is an essential part of a rifle that will play a huge role in its accuracy. Since you have an upper receiver included, having a barrel will help complete this part of the AR-10. Your barrel twist will also be something worth paying attention to. A certain ratio like 1:7 is a good number to look for if you hold accuracy to a high standard. Since your rifle is handling a rifle gas system, your barrels will probably be no shorter than 16 inches in length.

How We Chose These Build Kits

We chose these AR-10 build kits based on some of the characteristics we think will best fit you the buyer. These aspects and characteristics should play a role in your final decision purchase, especially if you are a first-time buyer of these kits. Here is a quick list of what to look out for based on people who have bought AR-10 build kits in the past:

What’s Included

The most important thing to look out for while you’re shopping for an AR-10 build kit is what’s included. Remember, some kits may include most parts you want. Some kits won’t have them. Knowing what’s included in a kit you’re looking at will make the decision easier. So, make a list of what you’ll need as part of your build kit. If it includes parts you already have, you can consider getting the kit anyways should you need any spare parts.

PSA MOE ACS-L EPT Lower Build Kit


We get it. Not everyone building an AR-10 will have expert gunsmithing skills. Their skills may be novice or intermediate. If you’re somewhere within that range, you should consider looking for a kit that will include “drop-in” parts. Drop-in is a fancy way of saying “easy to install”.

Most of the parts included in the kit will take minutes to install. So install one thing in as little time possible and move on to the next task on your list.


Quality will always trump everything else when you’re looking for gun accessories or kits. That’s because better quality will mean that longevity will be good. For example, some metal parts will usually be made from steel or aluminum, while other parts like magazines, buttstocks, and receivers will be made from polymer.

All these materials have been proven to handle all kinds of damage like weather, abuse, cleaning oils and solvents, and so much more. Having an AR-10 rifle that is tough from the inside out will give you the likelihood of using a rifle that will be reliable for years to come.

Cautious Considerations When Buying Build Kits

There are some additional considerations you’ll need before buying a build kit. These pertain to safety and also some potential legal issues. Here are some of the things you’ll need to consider when purchasing a build kit:

See if Everything You Need is Included

While accessories like the receiver and grips should always be included in each build kit, so should your springs, pins, and detents. Without any of these small parts, the rifle will be useless. Plus, you need to make sure every little part works properly, so you won’t have to deal with any malfunctions that may pose a safety hazard on your end.

Double Check Your Jurisdiction’s Gun Laws

Prior to purchasing a product, it’s always important to err on the side of caution, especially when it comes to gun laws. While it may sound ridiculous, there are some standalone AR parts that have restrictions and regulations due to gun laws in states like California, Illinois, or New York.

Check your local or state gun laws before you decide on a build kit for your rifle. It’s always good to check rather than face potential legal headaches in the future.

CMMG Inc MK3 Gunbuilder’s Lower Parts .308 Kit

Types of AR-10 Build Kits

Not all AR-10 build kits are the same. Some will include parts like both lower and upper receivers. Others will just include a standalone receiver (either lower or upper) with the parts included. Here are some of the types available on the market:

Upper Build Kits

These include AR-10 upper receiver. These uppers are typically available in two designs – the carry handle and the flattop. While carry handle has limited customization options, flattop has the many accessories available in the market.

Lower Build Kits

These include your lower receiver. Also included will be your trigger assembly and sometimes a barrel long enough to accommodate your rifle’s gas system. The lower receiver is responsible for housing your gun’s firing unit including the bolt carrying group, which is the engine for any AR-style rifle.

Rifle Kits

This kit is more of your “whole enchilada” kind of kit. This will include both an upper and lower receiver. Of course, it will also include parts for each respective half. Also included are things like your pistol grip, buttstock, and even a handrail that might be already attached to your barrel.


Finding the best AR-10 build kit can be a challenge. If you know what kind of parts you’re looking for, the search won’t be too hard. Whether you’re looking for a full rifle kit or a lower receiver kit to kick off your building project, you’ll be satisfied once you are able to complete your AR-10 rifle. Your hard work will pay off when you test it out at the range and it passes with flying colors. Find parts that are high in quality and will hold up their end of the bargain in terms of reliability.

People Also Ask

As an extra guide for your search, it’s important to refer to the frequently asked questions below. These are questions asked by most first-time buyers. If you’re among those who have never bought an AR-10 build kit before, then these will come in handy. Here are common questions:

Will an AR-15 Lower Parts Kit Fit an AR-10?

The short answer: it depends. The long answer: it will depend on the parts that you’re planning to install. Some parts like the hammer or trigger assembly may be compatible with one another. However, while some are interchangeable and work just the same, sometimes that won’t be the case.

What Calibers Fit an AR-10?

Some of the most popular calibers that will fit an AR-10 rifle are as follows: .308 Winchester, Creedmoor 6.5, or NATO 7.62.

Are AR-15 and AR-10 Stocks the Same?

Most of the time, they are. However, the difference between the two is their sizes. If the buttstock and screws fit both, it can be used. In fact, the buttstock is one of a handful of parts where it can be interchangeable between the two rifles. 

Josh Lewis the managing editor at Gun Mann and when he isn't writing about guns he is more than likely tinkering with them. He also enjoys hunting, fishing and spending time outdoors. As a lifelong gun owner he knows his stuff!

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