Building an AR15 is a great way to be introduced to the platform as it is considered a beginner’s friendly option that is easy to learn along with. AR-15 lower receivers are popular to customize the fire control group, and when looking to use a wildcat cartridge, such as a .300 Blackout – investing in a lower for this purpose allows compatibility with both .223 and 5.56 rounds if you ever plan on changing out the barrel.
Take a look at some of our best .300 Blackout lower receiver suggestions for anyone planning on an AR build. These are great options for both full custom builds, or a simple replacement for personal grip and feel.
Comparison Table of The 6 Best .300 Blackout Lower Receivers
BRAND
Bravo Company – AR-15 Complete Lower Receiver W/ Pistol Extension
DETAILS
- Multi-Caliber for use with 223 Remington, 5.56 mm NATO, 300 AAC Blackout
- Built to last with a Mil-Spec coating
- Comfortable for a wide variety of shooting styles
Strike Industries AR Enhanced Lower Receiver Parts Package
- Perfect for customized lower shooting experience
- Great price point
- Provides everything you need but the grip
PSA AR-15 “Stealth” Stripped Lower Receiver
- Basic stripped lower at a quality price point
- Room left for custom engraving
- Multi caliber to take in any direction you want
PSA AR-15 Complete Lower Magpul Moe Edition
- Accepts all Mil-Spec uppers
- Available in multiple finishes
- Durable 7075 aluminum
PSA AR15 MFT Minimalist EPT Lower
- Seriously smooth trigger with minimal take-up
- Multi caliber option for use with almost all AR15 caliber choices
- Minimalist looking with serious goods
Sharps Bros “Hellbreaker” AR-15 Stripped Lower Receiver
- Incredibly detailed
- Material quality use for long-lasting, durable shooting
- Compatible will GI standard issue mags and Pmags
The Popularity of the 300 Blackout
The AR-15 platform is a popular one because it is highly dependable, and built to accept a wide range of simple modifications to shoot a variety of caliber options. It also is easy to build from the ground up, allowing you to customize and personalize your fit, feel, comfort, and style at a comfortable price.
The 300 Blackout, also known as the 300 AAC, is a Wildcat cartridge that provides a nice caliber that fits well between the 5.56 NATO and classic .308 Win. It also is a great choice for both subsonic and supersonic shooting scenarios and has a recoil that is easy to control for hard-hitting accuracy.
If you are going to build your own, you want a dependable AR lower that fits your hand well and feels comfortably balanced when the upper is attached.
Lower Receiver Key Components
The lower receiver of an AR platform rifle connects to the upper receiver group to make a complete build. The lower includes the trigger group, magazine release, and buffer tube, safety selector, and a few other components. When looking to buy a lower you can either buy a completed lower group, or in separate, or stripped pieces, to assemble on your own.
Just a word of caution – the lower is hotly debated as the actual firearm since it contains the parts to fire the gun. Because of this, it is the most legally regulated part of an AR builds. The serial number is always located on the lower as well.
Trigger Groups
The trigger group includes the trigger and hammer, and trigger housing components. Triggers are one of the most customizable pieces you can take advantage of in terms of trigger pull weight and space you have for your fingers. The balance and overall feel can also be crucial to firing accuracy.
Buffer Tube
The buffer assembly is part of the recoil system and absorbs the majority of the kickback you feel to help make your shooting experience more comfortable. The buffer tube assembly houses both the buffer and buffer spring which work together to slow the firing action to protect the integrity of the frame. This is the key component that allows you to build short-barreled rifles without violating any sort of short-barreled firearm rules. Always be sure to use a pistol-length gas system if this is the choice you prefer.
Buttstock
The buttstock is part of the comfort feel of your rifle, and connects to the gun’s firing mechanisms. There are many traditional butt stocks out there to choose from to allow the perfect distance between your shoulder and rifle for balance while acquiring a target and shooting accurately. Plus, they are easy to swap out if you need a more comfortable butt stock option.
Grip
The grip is another custom piece that is part of the lower allowing you to get a good grasp for comfortable, balanced firing.
What to Watch For: A Quick Buyer’s Guide
Although most lower receivers are fairly similar in nature, there are crucial differences between various options you might want to pay close attention to in order to get exactly what you prefer.
Upper Receiver Compatibility
To complete a rifle build you need to connect both lower and upper receivers. Upper receivers allow the firing of the lower to be effective and house the barrel and related components. Of course, to modify an existing AR15 to fire with a 300 BLK cartridge, all you truly need is a new barrel.
But, if you are completely building from the ground up, or simply want a more personalized shooting experience, you may be buying one or both of the receivers – and they need to fit and work with one another. Because of this, you should stick with the same manufacturer for compatibility reasons and to get the specific fit questions you may have answered correctly.
Trigger Upgrades
Triggers and trigger guards are one of the most popular upgrades even without a full lower replacement. They are easy to switch out and can work to create a more sensitive shooting experience, a better balance for your hand size, and can help you with more accurate shooting. Consider the details of trigger types to determine which might be best for you if the standard aluminum factory trigger isn’t what you prefer. Mil-Spec triggers and ambidextrous trigger options are often sought out.
Single-Stage Trigger
This is your basic, go-to, standard trigger that comes with receiver kits and completed AR builds. They are simple, yet effective and rarely have any issues with creep or take-up. If anything, the 7 to 9 lb pull weight may feel heavy for some shooters who prefer a lighter option.
Two-Stage Trigger
Two-stage triggers have two points of contact before hammer release, usually with a light 2-pound force before releasing a heavier disconnector hook that gives way to a 2 or 3 pound pull weight before firing. This set-up allows a reduction in the amount of force applied before discharging and can work towards a more accurate shot as well as provide a safety feature.
Drop-In Trigger Options
If you like the lower receiver you have chosen but would like a simple trigger upgrade rather than a factory option, a drop-in trigger can provide a more custom feel. Drop-in options are self-contained and include the trigger, sear, hammer, and springs for quick, preassembled installation.
Caliber Compatibility
Even though the lower receiver is the true firing part of a gun, it is not what is specific to caliber, and a Blackout lower is compatible with multiple caliber rounds to make them more versatile in use.
Buttstock Options
The buttstock is another popular option for customization. This helps with personal comfort and balance and can aid in accuracy and recoil transfer. Most buttstocks on an AR build are adjustable to length, and some designs are made with padding or ergonomics for your own needs. They also are easy to swap out with after-market options if you need a more firm buttstock or traditional buttstock.
300 Blackout Lower Receivers Worth Taking a Closer Look At
We’ve gathered below some high-quality aluminum, AR-15 lower receivers for true AR-15 enthusiasts looking to replace or piece together their own .300 Blackout AR-15 build. The following options provide a friendly price to start with for what you might be looking for and offer a precision shooting range of choices no matter whether you are building for competitive Target shooting, or simply a fun day at the gun range.
1. Bravo Company – AR-15 Complete Lower Receiver W/ Pistol Extension
- Multi-Caliber for use with 223 Remington, 5.56 mm NATO, 300 AAC Blackout
- Built to last with a Mil-Spec coating
- Comfortable for a wide variety of shooting styles
Bravo Company (BCM) is well known for their excellent parts manufacturing and their complete lower receiver with pistol extension is a no-nonsense option that provides a simple, quality choice. Made from a machined 7075-T6 aluminum forging with a Mil-Spec hard coat anodized finish, it comes with all the small parts you need for reliable, long-lasting use.
The trigger is a proprietary Bravo Company made with a nickel teflon finish and is left un-notched to provide compatible 9mm use. The guard is also large enough for use with gloves when cold weather requires a bit more body protection. The Mod 3 pistol grip is another BCM make and is a standard choice popular with shooters due to its comfort level for a wide variety of hand sizes. And don’t forget the pistol receiver extension that is ready for a slip-on style brace with a BCM endplate and stalked castle nut.
Pros
- Multi-Caliber compatible for use with 223 Remington, 5.56 mm NATO, 300 AAC Blackout
- Built to last with a Mil-Spec coating
- Comfortable for a wide variety of shooting styles
Cons
- Slightly higher in price than similar options
2. Strike Industries AR Enhanced Lower Receiver Parts Package
- Perfect for customized lower shooting experience
- Great price point
- Provides everything you need but the grip
Lower receiver parts packages are a great way to truly customize your entire lower build. Complete with the trigger, hammer, disconnect, pins, springs, and the rest of the SI lower parts needed for a complete receiver, this Strike Industries option is a great choice for beginner builders.
Precision cut and phosphated for durability and protection against corrosion and wear, the fire control group offers 4.5 to 5.5 pounds of pull for control and smooth pulling comfort. An enhanced bolt catch and improved grip surfaces and angles are a perk shooters will enjoy for improved performance. Overall, this kit can be used for a build or to help boost the efficiency of an existing firearm. Note it does not come with a grip.
Pros
- Perfect for customized lower shooting experience
- Great price point
- Provides everything you need but the grip
Cons
- Does require more knowledge of a built to piece together
- Does not come with the grip
3. PSA AR-15 “Stealth” Stripped Lower Receiver
- Basic stripped lower at a quality price point
- Room left for custom engraving
- Multi caliber to take in any direction you want
Palmetto State Armory is a standard for firearm parts and accessories as well as carrying an excellent line of other quality gun part manufacturers. Their “Stealth” stripped lower is a basic option that offers the caliber (multi), model, and serial number with space for your own custom engraving logo. Forged from a 7075 Aluminum, it has a black hardcoat anodized finish per MIL-8625 Type 3 class 2 for long-lasting use and is quality made by a Mil-Spec contractor.
When you need a basic stripped option so you can take it in any direction you want, this is the perfect choice for use with lower parts kits, or customized pieces.
Pros
- Basic stripped lower at a quality price point
- Room left for custom engraving
- Multi caliber to take in any direction you want
Cons
- Not a full lower build
4. PSA AR-15 Complete Lower Magpul Moe Edition
- Accepts all Mil-Spec uppers
- Available in multiple finishes
- Durable 7075 aluminum
When you need a dependable classic, complete lower, this is an excellent MOE edition option available in a variety of popular colors to match your existing, or planned build. This PSA AR-15 complete classic lower is compatible as a MilSpec standard AR-15 part for use with all MilSpec uppers.
Made of high-quality 7075 Aluminum and provides a true quality choice at a great price point to offer a professional-looking option. Multi-caliber, it can handle a wide range of bullet sizes in an AR cartridge for all your AR platform needs.
Pros
- Accepts all Mil-Spec uppers
- Available in multiple finishes
- Durable 7075 aluminum
Cons
- May need a heavier spring for 180gr +
- Stock rocks slightly
5. PSA AR15 MFT Minimalist EPT Lower
- Seriously smooth trigger with minimal take-up
- Multi caliber option for use with almost all AR15 caliber choices
- Minimalist looking with serious goods
Palmetto State Armory knocks it out of the park again with their MFT minimalist EPT lower receiver machined from 7075-T6 aluminum forgings complete with a MIL-A-8625F, Type III, Class 2 hardcoat anodized finish. Even though considered a minimalist option, the lightweight design is all that is minimal. This is a packed option that boasts a Milspec diameter receiver extension, Mission First Tactical stock and engages grip, enhanced polished ETP trigger, and an un-notched hammer compatible with 9mm use.
Fully assembled and ready for complete upper, it offers a single-stage government-style fire control group with a super slick nickel finished trigger as an economical upgrade. It is ready for your complete upper for a personalized, multi-caliber finish!
Pros
- Seriously smooth trigger with minimal take-up
- Multi-caliber option for use with almost all AR15 caliber rifle choices
- Minimalist looking with serious goods
Cons
- May need to change out buffer and spring depending on caliber choice
6. Sharps Bros “Hellbreaker” AR-15 Stripped Lower Receiver
- Incredibly detailed
- Material quality use for long-lasting, durable shooting
- Compatible will GI standard issue mags and Pmags
Tired of the same old boring lower designs? Need something more exciting? Sharps Bros offers a series of semi-custom designs such as their Hellbreaker, skull, helmet, and even a warthog stripped lower receiver made of a hard-coated, corrosion-resistant aluminum alloy for use with all M4/AR-15 style rifles. These multi-caliber options are inspired by fighter plane nose art, and create amazing diversity when building your own personal AR platform rifle.
Unique, and yet made of amazing quality materials and workmanship, it boasts an oversized, integral trigger guard and beveled magazine flare for fast, efficient loading. Fully compatible with all Mil-Spec internal parts and upper receivers, you can truly create a customized option when you add the perfect trigger, grip, and comfortable stock for your own shooting experience. Plus, this awesome design will be the envy of all AR-15 owners when you bring it to the gun range.
Pros
- Incredibly detailed
- Material quality use for long-lasting, durable shooting
- Compatible will GI standard issue mags and Pmags
Cons
- Stripped offer only, must part the rest out
Conclusion
When shopping for a lower receiver or lower receiver parts kit, keep in mind you may likely need an FFL due to how the receiver is categorized – no matter how controversial. Of course, parts can always be shipped to a licensed professional gunsmith or business owner to help piece together the rifle of your dreams as well.
The options we’ve highlighted above are great choices, a reliable product, and offer excellent quality and manufacturing specs to ready the addition of your upper for a more customized shooting experience.
We’d love to hear about your favorite lowers, and what details make them the best in your mind. Leave your comments and questions below, and, as always, please share!