Top 6 Best .300 Blackout Upper Receivers (2020)

The .300 Blackout round is an extremely versatile projectile that was introduced in the firearms market to impart with an AR-15 with the power of a 308 caliber rifle. The .300 Blackout round is widely used for hunting due to its proper balance of weight, ballistics, size, and economics between the 5.56 and the 308.

If you already own a 5.56 AR-15 and you would like to switch to a rifle that chambers a .300 Blackout round, all it takes is just a change of an upper barrel. However, there are still certain factors that you should consider when looking for the best .300 Blackout upper receiver.

Buying Consideration for A .300 Blackout Upper Receivers

Construction

Like lower receivers, the .300 Blackout upper receivers are generally made from top quality aircraft-grade aluminum. Nonetheless, they can also be manufactured using different methods that include forging, billet machining, and casting.

If you want a .300 Blackout upper receiver that’s built to last, a forged upper receiver is widely known to be the most durable of all. That said, they might be heavier than others due to the greater density.

Cast receivers are known to be lightweight, but they are the weakest compared to the rest.

Billet receivers would fall somewhere between cast receivers and forged receivers in terms of strength and weight.

Stripped or complete

A stripped upper receiver is just a machined block without any components installed in it. Therefore, you have to buy the parts separately. That said, you will have lots of room for customization.

Complete uppers, on the other hand, would contain all the accessories and hence, the upper receiver can be installed and used right away. Since they have all the components you need, it’s more affordable.

Barrel

If you are looking for a complete upper receiver, you need to take a look at the length, rifling, profile, and the twist rate of the barrel. Longer barrels are great for long-range hunting, whereas the shorter ones are great for tactical and competitive uses.

Handguard and the top

Upper receivers can have flat tops or it could come with carry handles. In addition, the handguard can either be a simple one or it could have a mounting pattern. For better customization options, you would want to look for those that come with tactical handguards with flat tops and rails.

Top 6 .300 Blackout Upper Receivers Review

1. PSA 16″ Pistol-Length 300AAC Blackout 1/8 Nitride 15″

Specifications

  • Barrel Length: 16″
  • Gas System: Pistol Length
  • Barrel Profile: Heavy
  • Barrel Steel: 4150V Chrome Moly Vanadium
  • Barrel Finish: Nitride
  • Muzzle Thread: 5/8-24
  • Chamber: 300 AAC Blackout
  • Twist Rate: 1 in 8″
  • Diameter at Gas Block: .750″
  • Gas Block Type: Low-profile
  • Muzzle Device: A2 Flash Hider
  • Receiver Material: Forged 7075 T6
  • Bolt Carrier Group Included: Yes
  • Bolt Steel: Carpenter 158
  • Bolt Carrier Profile: Full-Auto
  • Charging Handle Included: Yes
  • Overall Length: 24.5″

Features

The PSA 16″ Pistol-Length 300AAC Blackout 1/8 Nitride 15″ is a complete upper receiver that’s forged using top quality 7075-T6 aircraft aluminum for enhanced durability. This is an M4-style upper receiver which will come with a forward assist, BCG, barrel, and a handguard.

The BCG is constructed from shot-penned 158-carpenter steel that features a full-auto profile for any rugged use. Besides that, the upper receiver also features nitride coating for better resistance against wear and tear. Also, it comes with a low profile pistol-length gas block that’s ideal for .300 Blackout rounds.

The PSA 16″ Pistol-Length 300AAC Blackout 1/8 Nitride 15″ has a chrome-moly vanadium 4150V barrel that’s chambered for the .300 Blackout round. Along with a stunning 1:8 twist rate, the barrel on this receiver would be able to handle both subsonic and supersonic .300 Blackout rounds exceptionally well.

Since this barrel is a heavy profile barrel, you won’t have any issues as you shoot continuous rounds over an extended period of time. Besides that, the muzzle features ⅝-24 threads so you can mount any suppressor or muzzle brakes on your .300 Blackout rifle.

Coming with the barrel is an A2 flash hider. This upper receiver also features the PSA 15’ lightweight, M-Lok rail, partial Picatinny rail, and a free-float handguard that doesn’t touch the barrel. The PSA 16″ Pistol-Length 300AAC Blackout 1/8 Nitride 15″ would be long enough for shooting mid-long range shots with great accuracy and precision.

You will like this product if:

You are shopping on a budget. The PSA 16″ Pistol-Length 300AAC Blackout 1/8 Nitride 15″ is a complete upper receiver that you can mount immediately. Besides coming with superb specifications, it comes at an affordable price as well.

You want a complete upper receiver. The PSA 16″ Pistol-Length 300AAC Blackout 1/8 Nitride 15″ is ready to fire after mounting it to your lower receiver. Since it’s a complete upper receiver, you won’t have to go around looking for other parts.

You might not like this product if:

You want to customize your rifle more. Well, the great thing about complete upper receivers is that you won’t have to look for any additional parts. However, if you want to customize your .300 Blackout rifle more, a complete upper receiver wouldn’t be your best buy.

2. ​PSA 16″ 300AAC Blackout 1/8 Nitride 13.5″

Specifications

  • Barrel Length: 16″
  • Gas System: Pistol Length
  • Barrel Profile: Heavy
  • Barrel Steel: 4150V Chrome Moly Vanadium
  • Barrel Finish: Nitride
  • Muzzle Thread: 5/8-24
  • Chamber: 300 AAC Blackout
  • Twist Rate: 1 in 8″
  • Diameter at Gas Block: .750″
  • Gas Block Type: Low-profile
  • Muzzle Device: A2 Flash Hider
  • Receiver Material: Forged 7075 T6
  • Handguard Type: PSA 13.5″ Lightweight M-Lok Rail Partial Picatinny Free Float
  • Bolt Carrier Group Included: Yes
  • Bolt Steel: Carpenter 158
  • Bolt Carrier Profile: Full-Auto
  • Charging Handle Included: Yes
  • Optics: Magpul MBUS Sight Set, Black
  • Overall Length: 24.5″
  • Weight as Configured: 4 lbs

Features

The PSA 16″ Pistol-Length 300AAC Blackout 1/8 Nitride 13.5″ is a pretty durable, feature-packed, at an affordable price tag from PSA. This upper receiver was forged from top-quality 7075-T6 aircraft-grade aluminum, which was built to last.

Featuring a pistol length gas system, the PSA 16″ Pistol-Length 300AAC Blackout 1/8 Nitride 13.5″ can handle both supersonic and subsonic .300 Blackout rounds so you won’t have to worry about your choice of .300 Blackout rounds. Besides that, it also comes with a low profile gas block.

Coming with a 16’ 4150V Chrome Moly Vanadium barrel with nitride finishing, your .300 Blackout rifle won’t have wear and tear issues when shooting under unfavorable weather conditions. Additionally, the muzzle comes with 5/8-24 muzzle threading so you won’t have compatibility issues when mounting on a suppressor or a muzzle brake.

In terms of versatility, the 1:8 twist rate of this barrel would work fine as it was designed to handle a wide range of operations. A notable feature of this upper receiver is that it comes with Magpul backup iron sights. These sights can be folded down when not needed, it can be used together with other optic scopes for better performance, and if you wish to switch it out, you can easily do so.

The PSA 16″ Pistol-Length 300AAC Blackout 1/8 Nitride 13.5″ comes with a flat top receiver that has a Picatinny rail if you wish to mount any scopes or optics. The handguard features M-Lok slots that would allow you to install slings and other accessories over your .300 Blackout rifle. Besides that, it also comes with a full-auto bolt carrier group for rugged use.

You will like this product if:

You don’t want to shop for any sights. If you want to take it straight to the shooting range, you can. This is all thanks to the pre-installed Magpul backup iron sights that you can rely on to shoot with high accuracy and precision on the range.

You might not like this product if:

You don’t want a heavy profile barrel. Heavy profile barrels are widely known to be great for shooting with high-rates of fire for extended periods of time. However, some shooters don’t need that, if you are one of them, then this might not be your best buy.

3. PSA 10.5″ Pistol-Length 300AAC Blackout 1/8 Nitride 12″

Specifications

  • Barrel Length: 10.5″
  • Barrel Profile: A2
  • Gas System: Pistol-length
  • Barrel Steel: 4150V Chrome Moly Vanadium
  • Barrel Finish: Nitride
  • Muzzle Thread: 5/8-24
  • Chamber: 300AAC Blackout
  • Twist Rate: 1:8
  • Diameter at Gas Block: .750
  • Gas Block Type: Low-profile
  • Muzzle Device: PSA Fluted Flash Can
  • Receiver Material: Forged 7075 T6 Aluminum
  • Handguard Type: PSA 12″ Slant End M-Lok Rail
  • Bolt Carrier Group Included: Yes
  • Bolt Steel: Carpenter 158
  • Bolt Carrier Profile: Full-auto
  • Charging Handle Included: Yes
  • Overall Length: 21″
  • Build Kit: MOE+ SBA3 EPT Pistol Kit, Black

Features

Wanna know what’s better than having a great .300 Blackout rifle? Having one that’s almost half the price, but just as great! Even if you have to assemble it yourself, this kit from Palmetto would be all that you need to set up a .300 Blackout rifle.

The PSA 10.5″ Pistol-Length 300AAC Blackout 1/8 Nitride 12″ is a kit that doesn’t only come with a complete upper receiver, it also comes with all the parts you need(except a lower receiver) in order for you to assemble a .300 Blackout rifle.

This upper receiver comes with a pistol length gas system with an A2 profile barrel that features a 1:8 twist rate to accommodate for a wide range of operations. In relation to durability, you know that this upper receiver was built to last when it’s forged from aircraft-grade 7075-T6 Aluminum which is durable enough to withstand harsh weather conditions.

Besides that, this upper receiver also comes with a slanted end, and a 12-inch M-Lok handguard with rails for you to mount any accessories you’d like. The muzzle of the barrel includes a fluted cash that can be removed to reveal its 5/8-24 threads for mounting your muzzle brakes and suppressors.

This lower parts kit will come with a fixed stock, buffer tube, pistol grip, and all your other components except a .300 Blackout lower receiver for you to assemble your Blackout rifle at home, at half the price.

You will like this product if:

You are on a tight budget. Available for less than $500, you have all you need, except for a lower receiver to build a great quality .300 Blackout rifle at home, at half the cost. If you want to customize your gun, you’re free to do so too as you will be building it.

You might not like this product if:

You want a lighter trigger. Unfortunately, some users have complained about the trigger provided in the kit felt a bit heavy. If you don’t like heavy triggers, then this wouldn’t be your best buy.

4. PSA 8.5″ 300AAC Blackout 1/7 Nitride 2A Armament 10″

Specifications

  • Upper Receiver Type: Forged Standard
  • Upper Receiver Material: 7075 T6 Aluminum
  • Upper Reciever Coating: Hardcoat Anodized
  • Muzzle Device: PSA Fluted Flash Can
  • Barrel Caliber: 300AAC Blackout
  • Barrel Profile: Heavy
  • Barrel Material: 4150V CMV
  • Barrel Length: 8.5″
  • Barrel Thread Pitch: 5/8 x 24
  • Barrel Twist Ratio: 1:7
  • Gas Block Size: .750
  • Gas Block Type: Low Profile
  • Gas System: Pistol
  • Handguard Length: 10″
  • Handguard Type: M-LOK
  • Handguard Color: Black
  • Rail Profile: Standard
  • BCG Caliber: 5.56
  • BCG Profile: Full Auto
  • BCG Bolt Type: Carpenter 158
  • Charging Handle: 7075 T6 Aluminum

Features

If you are looking for an SBR or a .300 Blackout pistol, the PSA 10.5″ Pistol-Length 300AAC Blackout 1/8 Nitride 12″ would be your answer. This receiver is great in terms of durability seeing that it’s forged from 7075 T6 Aluminum and hard coat anodized to resist any wear and tear.

The length of the barrel for the upper receiver is 8.5’ and it has an incredible twist rate of 1:7 inches. As such, you will have no issues in chambering supersonic and subsonic .300 Blackout rounds with extreme accuracy and precision.

Coming with a nitride finishing, the PSA 8.5″ 300AAC Blackout 1/7 Nitride 2A Armament 10″ won’t accumulate much grime and hence, only minimal maintenance is required. The full-auto profile BCG on this upper receiver is constructed from carpenter 158 steel and will run very smoothly.

This upper receiver can easily be mounted on a pistol lower receiver. However, when it comes to mounting it on a regular rifle-sized lower, you might have to overcome some legal issues.

The barrel of this upper receiver has a flash that’s threaded over the 5/8 x 24 muzzle. In addition, this upper comes with a full-length rail from the receiver up to the tip of the handguard. With that, you can mount slings and other accessories to your .300 Blackout rifle with ease.

You will like this product if:

You want to mount more accessories. Featuring a full-length rail from the receiver up to the tip of the handguard. With such a rail, you will be able to mount more accessories on your .300 Blackout rifle to enhance your shooting experience.

You might not like this product if:

You want to shoot mid-long range shots. The PSA 8.5″ 300AAC Blackout 1/7 Nitride 2A Armament 10″ is a pistol-length barrel. If you want to shoot longer ranges, a rifle lengthed barrel would be a better option.

5. Smith & Wesson M&P AR15 Whisper

Specifications

  • Cartridge: 300 AAC Blackout
  • Finish: Black
  • Length: 16
  • Style: Assembled
  • Twist: 1-7
  • Made in the USA
  • Low recoil and muzzle blast
  • Comes “optic ready” – no front or rear iron sights
  • Low-profile gas block with integral Picatinny rail
  • Yankee Hill Phantom flash suppressor keeps flash signature to a minimum

Features

Most people are sold from the name of Smith and Wesson itself because they know, if it’s a Smith and Wesson product, what could go wrong? The Smith & Wesson M&P AR15 Whisper is perhaps the most traditional upper receiver you can get in the market.

The Smith & Wesson M&P AR15 Whisper is a full-sized carbine that comes outfitted with a 16’ barrel and a 1:7.5’ twist rate and a threaded muzzle. As such, you can easily mount any suppressors or muzzle brakes on your gun. A notable feature of this product is that it comes with the Yankee Hill Phantom flash suppressor, which is a really nice touch.

The Smith & Wesson M&P AR15 Whisper features a flat top upper so that you’ll be able to mount your optics on it. This upper receiver was specifically designed for the .300 Blackout round and adopts a gas system to function well with both subsonic and supersonic .300 Blackout rounds.

Although the quad rail might seem a little out of place in the days of the M-Lok and Keymod, the Smith & Wesson M&P AR15 Whisper is a simpler system. At the cost of only a little extra weight, you’ll be getting a more robust upper receiver.

Coming with a 10’ long handguard, the weight is just right. The Smith & Wesson M&P AR15 Whisper is a complete upper receiver, so it will come with a charging handle and a bolt carrier group.

You will like this product if:

You are a Smith and Wesson fan. With Smith and Wesson being one of the most well-known players in the firearms industry, they have gained lots of loyal customers over their track record of producing great quality firearms and firearm accessories, and the Smith & Wesson M&P AR15 Whisper is one of them.

You might not like this product if:

You are shopping on a budget. Although there is no doubt that you will be getting great value from the Smith & Wesson M&P AR15 Whisper, its price tag isn’t friendly to everyone, especially if you have a tight budget.

6. Aero Precision M4E1 Assembled Upper Receiver .300 BLK

Specifications

  • Cartridge: 300 AAC Blackout
  • Contour: M4
  • Finish: Black
  • Length: 8
  • Style: Assembled
  • Twist: 1-7
  • Made in the USA
  • M-LOK EM-7 7” for 8” barrel
  • Pistol length gas system w/ low profile gas block
  • Standard A2 flash hider

Features

Many shooters are opting for a 10’ barrel on an AR pistol to be chambered in a .300 Blackout round. If you are one of them, then the Aero Precision M4E1 Assembled Upper Receiver .300 BLK is going to be one of your favorites.

The upper receivers from Aero Precision all feature different lengths of handguards so you’ll have the freedom to choose according to your preferences. The barrel on this upper receiver will be equipped with the standard A2 muzzle brake that’s been proven over time to be pretty efficient and effective.

The muzzle device on the Aero Precision M4E1 Assembled Upper Receiver .300 BLK isn’t fixed so you can easily attach your muzzle devices according to your personal preferences. The Aero Precision M4E1 Assembled Upper Receiver .300 BLK all sport the same pistol length gas system that works really well with subsonic and supersonic .300 Blackout rounds.

Aero Precision makes really great quality gear that’s been proven to be everyone’s favorite overtime. That is why they would be perfect for your next .300 Blackout rifle build or for converting your 5.56 rifle to a .300 Blackout.

You will like this product if:

You want to mount optics. The Aero Precision M4E1 Assembled Upper Receiver .300 BLK comes with a really great flat top upper to meet your needs when it comes to mounting optics. Many scopes and optics will work well with this upper.

You might not like this product if:

You want pre-installed iron sights. Unfortunately, this upper doesn’t come with pre-installed iron sights unlike some of the ones on this list. That said, the Aero Precision is still a great upper receiver only this as its shortcoming.

Frequently Asked Questions (FAQ)

Can you shoot a .300 Blackout round from a 5.56 barrel?

Although the .300 Blackout rounds won’t have any issues chambering into a 5.56 barrel, it will literally burst explosively when you try to shoot it. So never ever do something like that, don’t even try.

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