Best .300 Blackout Lower Receivers – 2024 Top Picks

| Last Updated:
September 13, 2023

The 300 blackout was the answer for the extremely popular 7.62x39 AK-47 rounds. The AR-15 was to be upgraded with a more powerful bullet with better ballistics while keeping almost all of the parts interchangeable between the .223 and 300BLK caliber.

But it's always best to build a 300BLK AR with a dedicated lower receiver. 

Comparison Chart of the Best .300 Blackout Lower Receivers

  • Includes Pistol Grip and Buttstock
  • Fits Most AR Rifles, Regardless of Caliber
  • Machined From High-Quality Aluminum Forging
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  • Fits Multiple Caliber AR Rifles
  • Machined from 7075 Aluminum
  • M4 Stock for Added Support and Recoil Resistance
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  • Fits Most Calibers
  • Safe/Fire Feature for Safeties
  • Crafted From High-Quality Aluminum
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Factors to Consider Before Buying 300 BLK Lower

Before you start scouring our list for a 300 blk lower receiver. It is imperative to look at a few important considerations that’ll be beneficial for you in the long run. 

Ankit Kumar - Writer for

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Ankit Kumar

Expert Author

Ankit Kumar is an engineer turned writer who specializes in topics related to firearms, gun safety and weapon tech. His passion towards enrolling in the Army drifted his interest towards light and heavy firearms. He’s a qualified competitive air rifle shooter and an avid nature lover. His other areas of expertise include survival, prepping and firearms/ammo storage. When he’s not writing, he’s either learning a new skill, trekking or enjoying a long drive.

Forged or Machined Lower

The lower receiver handles very little pressure compared to the upper receiver. But having one that is durable enough is crucial for a sturdy overall rifle build. Forged receivers have always been a sturdier option compared to machined lowers. However, their finish is a tad crude and you’ll not get as many aesthetic features. 

Best Gas System Length and Buffer

The 300 blk is a heavy round and operates best with short barrels and gas system length. Pistol length gas systems are best suited for this caliber. Since longer systems like carbine and rifle will generally result in ineffective cycling. 

Apart from that, having a suitable buffer on your rifle will also help with effective cycling and also the mitigation of recoil to some extent. Since the 300 blk utilizes a pistol-length gas system, you should understand that there isn’t enough gas to cycle a heavy buffer usually. So when working with subsonic 300 blk rounds, you may prefer switching to a lighter buffer. 

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Always Mark Your Rifle

The 300 blk is just a necked-down variant of the .223 case. So a 300 blk round will seat inside the barrel of a .223. But once you pull the trigger, the outcome will be catastrophic. It has been noticed quite often that people unknowingly feed .300 mags into a .223 AR. 

The right solution is to keep your magazines and rifles marked and visually inspect when loading rounds inside the magazine. 

Complete or Incomplete Lower

Technically, the lower receiver is considered to be the firearm and is required to be sold by an FFL dealer. That is why 80% lowers exist on the market that bypasses this law and can be sold without any of such legal formalities. 

Many people who don’t want to go through these legalities or want a more customized lower receiver for their build, opt for these incomplete lower receivers. 

Others who want a finished product and do not want to put in unnecessary effort in customization opt for complete receivers or lower parts kits. 

Review of the Best .300 Blackout Lower Receivers

Below are the best .300 Blackout lower receivers currently on the market right now.

Prior to making a decision, read through each one of these reviews carefully. You might find one to be a suitable replacement for your current lower receiver. Or, if you're building a rifle, this is the perfect time to find a lower receiver that will look good and function well once the rifle is complete. With that said, let's get started:

Best Overall:
PSA AR-15 Complete Rifle Lower Receiver A2


  • Easy to Install
  • A Great Alternative for Users Who Don’t Like Adjustable Stocks
  • Can Eliminate a Lot of Recoil With the Pairing of a Good Muzzle Brake


  • The Overall Fit May Not Be as Tight as Expected
  • Some Have Complained About the Stock Being a Little Loose
  • Some Are Not Too Happy With the Trigger Installed on This Lower

Next, we'll be taking a look at the PSA AR-15 Complete Rifle Lower Receiver A2. Compared to our previous product, this stock is designed to look like a standard rifle stock. If that's the kind of design you want for your .300 Blackout rifle, this might be worth looking into.

This is machined from aluminum forging that is designed to be tough as nails and able to handle the duties of a powerful rifle like an AR rifle capable of firing off .300 Blackout rounds.

This will not only fit .300 Blackout rifles but will also work with multiple caliber AR rifles. It doesn't matter if it's a 5.56 or a .223, this product is versatile and can fit pretty much any rifle in the AR category. If you have other AR rifles, it might be worth getting an extra one if you got some money to work with.

The lower receiver includes the usual trigger assembly but also includes a pistol grip and buttstock that is designed to give you better control over your .300 Blackout rifle. Remember, if you have good control and the ability to resist a good deal of recoil, your rifle can be dangerous in terms of accuracy. If you hold accuracy to a high standard, this might be able to help you control your rifle and reduce as much recoil as possible.

Bottom Line

This PSA lower receiver gives you the classic look and function of a rifle. If that’s something that you hold a deep appreciation for, then you’ll have no problem choosing this over the others. As mentioned before, this is compatible with just about any other AR rifle out there.

So the versatility and the ability to work with these rifles is quite impressive. If you’re looking for a go-to lower receiver for all your other AR rifles (if you have any others in your collection), go with this PSA product.

2. PSA AR-15 Complete Classic Lower


  • Great Durability for a Military-Style Lower Receiver
  • Fits Perfectly With Most Pre-Assembled PSA Uppers
  • Excellent Lower Receiver Alternative for Budget Shoppers


  • Trigger is a Little Gritty Upon Initial Use
  • Some Have Complained About the Trigger Pull

Next, we’ll be taking a look at the AR-15 Complete Classic Lower. Aside from the material it is machined from, this includes an M4 stock designed to give you maximum support and the ability to resist as much recoil as possible. Since the material is synthetic, this will have the ability to withstand a good deal of shock.

On top of that, this can also handle the worst weather conditions you can find yourself in. If you’re out on the range or in the field and it’s raining like crazy, you won’t have to worry about the stock getting damaged.

The good news is that this can fit almost any caliber within the AR category, including .300 Blackout rifles. The even better news is this puppy is fully-assembled and ready to go just as soon as you install it. If you want a classic lower that will function properly right out of the box, this is the one you’ll want to have on your rifle.

Bottom Line

If you’re looking for a good, fully-assembled product for your .300 Blackout, this complete classic lower may be your best option. Everything is assembled and in place, ready to go once it is installed.

The installation process is quick, so you might be able to give this a whirl on the same day. This is also a good product to have if you want something that’s as close to a military style as possible.

3. PSA AR-15 Lower Safe/Fire


  • Excellent as a Starter Lower Receiver
  • A Well-Machined, Durable Lower Receiver
  • Functions Very Well After 200+ Rounds Without Issue


  • Some Have Complained About Issues With the Trigger
  • One Reviewer Complained About This Lower Being Loose in Fit
  • One Reviewer Has Complained About the Trigger Pin Not Staying in Place

For our last lower receiver on the list, we'll be taking a look at the AR-15 Lower Safe/Fire. The material this is made from is technology designed from an unlikely industry. More specifically, we're talking the aerospace industry.

If you decide to go with this product and you're satisfied, you'll have to thank the fine folks at NASA for developing the technology responsible for putting this together. Aside from that, this has a safety that will let you know when it's safe and when it's live and ready to fire (hence the name Safe/Fire).

Aside from that, this is crafted from high-quality aluminum and is designed to fit a .300 Blackout rifle and even other rifles within the AR category. For added durability, the anodized black finish is added, so this will be a tough as nails kind of lower receiver that will last you a good while.

Bottom Line

The Safe/Fire feature is a convenient addition to this lower receiver. If you’re looking for something that will fit perfectly with something like an ambidextrous trigger, this might be the one that could do the trick.

Other than that, this is one tough customer designed to last you a good deal of time so long as you take great care of it .300 Blackout rifle and clean it as often as every 500 rounds. Take care of your rifle and your rifle will take care of you no matter the purpose you use it for.

4. PSA AR-15 MOE EPT Lower


  • Pairs Perfectly With Most PSA Uppers
  • Secured Properly in All the Right Places
  • Trigger Pull is Great. No Creep to Speak of


  • Some Say the Trigger Pull is a Little Heavier Than Expected
  • Some Complained About the Stock Being Very Loose and Sloppy

Our first lower receiver up for review is the PSA AR-15 MOE EPT Lower. To begin, you'll notice that this is a super strong and durable lower. That's because it is crafted from high-quality 7075 aluminum.

You'll be seeing this kind of aluminum in most lower receivers and other parts as well. This type of aluminum is perhaps one of the strongest materials used by manufacturers. Not only is this designed to be just a lower receiver, but it also comes with the convenient little addition.

That addition is none other than a buttstock made from synthetic materials designed to help the stock reduce recoil and absorb shock. .300 Blackout rifles do pack a heavy punch, so expect the buttstock to help in reducing as much recoil as possible.

Equipped with this product is a PSA AR15/PA10 trigger. This trigger is a mil-spec trigger that is nickel finished and provides a smooth, crisp pull each time you use it. If you want to get a shot off quickly, you want a trigger with a light amount of pull weight but just enough for you to not apply too much pressure.

If you’re looking for a reliable product for your .300 Blackout, the PSA AR-15 MOE EPT Lower might be your best possible choice.

Bottom Line

The PSA lower receiver has proven itself to be deserving of the best overall honor. We don’t regret that in the slightest. While the trigger pull may be an area of concern for some users, it can still pull just as well as any other mil-spec trigger on the market.

The buttstock is a perfect inclusion with this item and will definitely save you some money as opposed to purchasing a buttstock separately. If you’re looking for the best of the best when it comes to lower receivers, the PSA AR-15 MOE may very well be the one you choose.

5. PSA AR-15 Complete MOE EPT SBA3 Lower


  • Easily Adjustable
  • Trigger Pull is Crisp and Creep-Free
  • Collapses Smoothly Like Many Other Adjustable or Collapsible Stocks


  • Some Have Had Issues About the Safety Selector Being a Little Crooked
  • Some Are Not Happy With the Aluminum Factory Trigger That is Included
  • Upper and Lower Fit Should be Tighter. It Would Depend on Which Upper is Paired With This Lower in Particular

If you’re on a budget, don’t consider yourself left out. You’ll be able to find a decent lower receiver for your .300 Blackout rifle. And what better one to find than the PSA AR-15 Complete MOE EPT SBA3 Lower?

This product is made from high-quality aluminum and has a receiver extension made from the same type of aluminum. Of course, this will withstand the punishment a .300 Blackout rifle can dish out.

This has an enhanced, polished trigger designed to give you a mil-spec style pull, meaning the trigger pull will be slightly heavier than most, but you’ll still be able to get a no-creep trigger pull each time.

The buttstock is designed to absorb a great deal of shock and to give you the best in overall rifle control. If you’re looking for a product that is reliable and won’t break the bank, you should give the SBA3 lower a closer look.

This is compatible with most PSA brand uppers, so if you need an upper as well, kill two birds with one stone and get this lower along with an upper that can accommodate each other.

Bottom Line

If you're looking for an excellent lower receiver that fits your budget, this will no doubt be the best option for you. The collapsible stock is convenient for those who don't want to struggle with dealing with a so-called "one size fits all stock".

If you want the reach of your .300 Blackout rifle to be dead-on with the right adjustments, this stock will offer you that luxury. As expected, this is more than those usual "you get what you pay for" kind of accessories.

We only find the best in quality at a price that will fit most budgets, because quality and performance shouldn't be reduced just because of the price tag.

300 Blackout’s Compatibility With AR-15

When the .300 Blackout burst onto the scene years ago, AR-15 owners and enthusiasts were quick to embrace it. One of the reasons is that the .300 Blackout, especially its rifles, were able to allow AR-15 magazines to fit without any issues. Actually, let’s rephrase that. It can handle pretty much every standard AR-15 part and accessory you can possibly think of.

But can you fire .300 Blackout cartridges in AR-15 magazines built for other rounds? If you have a magazine that is built to take on 5.56 NATO rounds, then the answer is yes. However, it probably won’t be compatible if you have a magazine that typically chambers .223 rounds.

What parts need to be changed to help accommodate Blackout cartridges? Once again, 5.56 rifles may not apply to any possible adjustments. But a .223 caliber rifle may need to be fully converted to handle such rounds.

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What Are The Components of a Lower Receiver?

To know the ins and outs of a lower receiver, you need to know some of the parts that comprise of it. In short, the lower receiver contains the fire control group of your .300 Blackout rifle. The same applies for this part on any other AR-15 rifle.

The lower receiver is made of the trigger, disconnector, fire selector, magazine catch, and the hammer. In plain English, the trigger assembly and the magazine are the two most important components that are housed in the lower receiver.

It is also secured to the upper receiver using two pins. The split design of having two receivers will allow the upper part to have more customization abilities.

What Makes a Great .300 Blackout Lower Receiver?

Before choosing a lower receiver for your .300 Blackout rifle, you have to know what exactly makes one great compared to the cheap, low-quality models. We recommend that you take some time while choosing one so you can find the best that is great in quality and also efficient in doing its intended purpose. If you have no idea what to look for, here’s a list of recommendations based on what past buyers have said:

Does it Fit Your Barrel?

The important question to ask yourself is: will this fit my barrel perfectly? Remember, not all .300 Blackout barrels are of the same length. Some are as short as nine inches, while others are as long as 20 inches or more. Either way, you need to find a lower receiver that will accommodate a barrel that is of the specified length.


Of course, not every .300 Blackout owner will be a skilled gunsmith. So it’s important to find a product that will allow you to install it with ease. Some use of tools may be required, but it should be easy enough you don’t have to enlist the services of a professional gunsmith. The key word to look for in your search for a lower receiver is “drop in”. In plain English, this translates into easy to install.

Does it Fit Your Upper?

A good lower can’t stay in place if you can’t find an upper that is compatible. It is highly recommended that if you find a lower receiver from a certain brand, find an upper from them. Not all uppers from the same brand fit perfectly, so it’s important to do a little in-depth research to figure out which one will be compatible with the lower receiver you choose.


Finding the best .300 Blackout lower receiver doesn’t have to be a challenge. It’s important to find one that will last you a long time and is able to fit properly with an upper of your choice. Since all of these are of the PSA brand, it’s highly recommended that you should pair the lower of your choice with an upper from PSA. Once you have it put together, you’ll be ready for action and so will your .300 Blackout rifle. 

Michael Lutes

Michael Lutes is the managing editor and owner at Gun Mann. He is a veteran, gun enthusiast, 3 gun competitor, and 2a advocate. Mike has a passion for innovation and education across the industry to create great content, training, and insights from the best and brightest.

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