5 Best 300 Blackout Magazines: Tested and Reviewed!

by Kat Ainsworth-Stevens

December 29, 2023

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Having the correct magazine on hand is a must, as is having more than one. If you’re an AR-15 owner, you probably have more than a few mags, but what if you have multiple calibers? For example, do you know which magazines are the best for your 300 Blackout? Do you have separate magazines for your 300 Blackout instead of mixing them with the magazines for your 223 Remington? We’ve picked out some of the best 300 Blackout magazines on the market to save you some of the guesswork, and we’re going to explain why they work so well.

Explaining the 300 Blackout magazine

We know what you’re thinking: 300 Blackout magazines are really just standard AR-15 magazines. While you wouldn’t be entirely wrong to assume that, it’s also true that some AR-15 magazines work better than others for this popular close quarters cartridge. It’s also wise to have magazines dedicated—and marked—as being specific for your 300 Blackout. That way, you avoid any errors that could cause a catastrophic failure.

So, what parts does a 300 Blackout magazine have? The parts of these mags are standard to AR platform mags and include the body, spring, follower, and floor plate. Those components can be made from a variety of materials, whether that’s some combination of types of metals or plastics or a hybrid that includes both (most, but not all, include both). Colors and textures vary right down to the followers, and they can mark base plates at the factory with calibers or other designs, as can the magazine bodies.

Not all magazines perform equally in all firearms, either. Just because a magazine manufacturer states it’s intended for the AR-15 platform doesn’t mean it’s going to do what it should, reliably. It’s important to understand there might be some trial and error before you find your favorite mags. And when you do find them, it’s a good idea to stock up.

Best 300 Blackout Magazines

How We Chose the Best 300 Blackout Magazines

If you are diving into the world of 300 Blackout you should probably plan on doing some testing and fine tuning. From the guns to the ammo, there are many variables. That can make things a lot of fun, or somewhat annoying, depending what you like to do. The magazines you use in your 300 Blackout are a variable not to be overlooked.

Shooting AR with Single Stage Trigger

Since we at Gun University enjoy tinkering and trying new things out, we enjoyed the testing process. So if you don’t, we have you covered. Although, you should probably do a little bit of testing on your end still.

We have ran various 300 Blackout setups over the years and have found what magazines have worked best for us. Wile you probably don’t need to try all the magazines on our list, based on our reviews and your usage, you should be able to narrow down the ones for you to test. This way you can spend more time enjoying shooting, and less time clearing malfunctions from improper magazine compatibility.

Gun University’s Choices of the Best 300 Blackout Magazines

Best Products

Magpul PMAG 30 AR 300 B Gen M3, 300 BLK
  • Purpose built for 300 BLK
  • Polymer body
  • Distinct texture from 5.56 variant
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Amend2 AR-15 30-round 300 BLK Mod-3
  • Fiberglass reinforced nylon body
  • Stainless steel spring
  • 4 way anti-tilt follower
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Lancer Systems L5AWM 300 BLK 30 Magazine
  • Translucent body to see round count
  • Steel feed lips
  • Designed for subsonic ammo
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Duramag Speed AR-15 20-round Aluminum Magazine
  • Aluminum body
  • Battle proven
  • Teflon coating
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Sentry Hexmag AR-15/M4/M16 Replacement Magazine (Series 2)
  • Tool-less design for maintenance
  • HexID color coding system
  • Polymer body with hexagon texture
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Spec Comparison of the Best 300 Blackout Magazines

Below is a table of the specifications for the best 300 Blackout magazines.

MagazineCapacityWeight (oz)Length (in)Material
Magpul PMAG 30 AR 300 BLK3057.5Polymer
Amend2 AR-15 30 Round 300 BLK305.447.5Fiber Reinforced Nylon
Lancer Systems L5AWM  300 BLK304.87.375Polymer
Duramag Speed AR-15 20 Round Al Magazine203.2N/AAluminum
Sentry Hexmag Replacement Magazine304.87.6PolyHex2 Advanced Composite

Best Products

For this roundup, we’ve chosen a specific set of magazines, each of which offers something different. After all, they might seem the same, but they’re not. The best 300 Blackout magazines are:

  1. Best overall: Magpul PMAG 30 AR 300 B Gen M3, 300 BLK Magazine
  2. Best for Duty: Amend2 AR-15 30-round 300 BLK Mod-3 Magazine
  3. Best See-Through: Lancer Systems L5AWM 300 BLK 30 Magazine
  4. Best Metal: Duramag Speed AR-15 20-round Aluminum Magazine
  5. Best Budget Friendly: Sentry Hexmag AR-15/M4/M16 Replacement Magazine (Series 2)

Best 300 Blackout Magazines – Reviews 

When you’re choosing a magazine, there are a few key things to consider: Does the magazine feed reliably? If it’s dropped, does the magazine immediately fall apart, or can it survive some rough handling? Is the body and exterior of the magazine marked or can we mark it so you know what caliber it holds? Does the magazine have a long spring and function life? Let’s check out some of the best 300 Blackout magazines on the market and consider what makes them such great choices.

1 Magpul PMAG 30 AR 300 B Gen M3 300 BLK : Best overall

Magpul PMAG 30 AR 300 B Gen M3 300 BLK Featured Image

Magpul PMAG 30 AR 300 B Gen M3 300 BLK

A polymer magazine that has been, and still is, the industry standard magazine for durability and reliability. Now it comes in a dedicated 300 Blackout variant with unique texture to help set it apart from its 5.56 counterpart.

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  • Reliability A+
  • Features A-
  • Fit A
  • Value A

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A

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Magpul PMAG 30 AR 300 B Gen M3, 300 BLK Specs

  • Capacity 30
  • Weight 5 oz
  • Length 7.5 in
  • Material Polymer

Magpul PMAG 30 AR 300 B Gen M3, 300 BLK Review

Magpul has a well-deserved reputation for designing and manufacturing well-made parts and gear, and we know their PMAG line for being rugged and reliable. The Magpul PMAG 30 AR 300 B Gen M3, 300 BLK, is a durable magazine designed specifically for AR-15s chambered in 300 Blackout. The manufacturer describes this Gen M3 magazine as a purpose-driven mag, and it really is. After all, it’s not every AR mag out there that’s designed for the greatest possible performance with the 300 Blackout—but they make this one for just that.

This magazine has a durable polymer body made to be impact and crush resistant. The floor plate is easy to remove—but stays in place reliably—so you can clean and maintain the magazine as needed (yes, you’re supposed to maintain your mags). To differentiate this mag from the 223 Rem/5.56 NATO mags in the PMAG line, Magpul gave this magazine a distinct rib design on its lower half, leaving the upper half of the body smooth. That means shooters have not only a visual but a tactile way to differentiate between magazines.

The Magpul PMAG 30 AR 300 B Gen M3 is optimized for use with 300 Blackout because they made it according to the specific geometry of that cartridge. This translates to greater reliability. This magazine is marked with “300 BLK” on the side, in addition to its body design that helps shooters distinguish between calibers. It measures 7.5 inches in length, weighs 5 ounces empty, and is largely compatible with the majority of STANAG 4179 platforms like the AR-15, FN SCAR, and IWI Tavor. It has a 30 round capacity. This is a fantastic magazine for all shooters and delivers with consistent, reliable feeding and a long life.

Magpul PMAG 30 AR 300 B Gen M3, 300 BLK Pros and Cons

  • Exceptional durability
  • Reliable feeding
  • 300 BLK specific
  • Higher price point

2 Amend2 AR-15 30-round 300 BLK Mod-3 : Best for Futy

Amend2 AR-15 30-round 300 BLK Mod-3 Featured Image

Amend2 AR-15 30-round 300 BLK Mod-3

A fiberglass reinforced nylon magazine that has an anti-tilt follower.

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  • Reliability A
  • Features B+
  • Fit A
  • Value A-

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A-

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Amend2 AR-15 30-round 300 BLK Mod-3 Specs

  • Capacity 30
  • Weight 5.44 oz
  • Length 7.5 in
  • Material Fiber reinforced nylon

Amend2 AR-15 30-round 300 BLK Mod-3 Review

The Amend2 AR-15 30-round 300 BLK Mod-3 is designed for 300 Blackout compatibility rather than being offered as a multi-caliber product. This latest generation of the popular magazine line offers a host of enhancements such as new aesthetics, resins, and features. It’s made to be even better than the Mod-2 line of magazines and it proves its worth in the field.

This magazine has a body made from fiberglass reinforced nylon to provide the user with incredible durability and resistance to the impacts of hard use. It has fantastic rigidity and is made to be resistant to extreme temperatures. The magazine’s overall aesthetics and texturing give the user a sure grip during magazine changes. According to Amend2, they made this magazine to fit in better in a duty use environment by giving it a less flashy and more muted design.

Other features of the magazine include an anti-tilt follower, Cerakote-compatible body, and recognizable 2 on the base plate. The spring of this magazine is heavy duty, non-corrosive, and made to be non-memory, meaning it’s designed not to lose its shape and functionality. This magazine has a 30-round capacity. Whether you’re a hunter, sport shooter, or defender, the Amend2 AR-15 30-round 300 BLK Mod-3 magazine is a great fit.

Amend2 AR-15 30-round 300 BLK Mod-3 Pros and Cons

  • Reliable function
  • Temperature resistant
  • 300 BLK specific
  • Not clearly marked for 300 BLK

3 Lancer Systems L5AWM 300 BLK 30 : Best See-Through

Lancer Systems L5AWM 300 BLK 30 Featured Image

Lancer Systems L5AWM 300 BLK 30

A translucent polymer magazine with metal feed lips that has been designed for heavy, subsonic 300 Blackout ammunition.

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  • Reliability A
  • Features A-
  • Fit A
  • Value A-

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A

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Lancer Systems L5AWM 300 BLK 30 Magazine Specs

  • Capacity 30
  • Weight 4.8 oz
  • Length 7.375 in
  • Material Polymer

Lancer Systems L5AWM 300 BLK 30 Magazine Review

Sometimes it’s nice to confirm your round count—at least approximately—at a glance, and that’s where transparent mags come in. The Lancer Systems L5AWM 300 BLK 30 Magazine offers this feature, along with being reliable and well-made. This is another magazine that’s engineered for ideal performance with 300 Blackout, and that’s a must if you want the best magazine possible for your AR-15. Lancer states the L5AWM is made for heavy subsonic 300 Blackout with updated internal geometry that facilitates smooth, consistent feeding. Not all AR-15 mags will reliably feed heavy subsonic rounds, but this Lancer design does.

For a distinct touch that sets it apart from 223 Rem/5.56 NATO magazines, the Lancer L5AWM is stamped with large 300 BLK markings. This drastically reduces the risk of using the magazine in the wrong firearm. They offer the magazine with either a translucent smoke or opaque black body, the former which is great for a see-through mag and the latter of which blends in nicely with most AR-15s. Magazines also have an FDE (flat dark earth) base plate to mark them even more noticeably as being for the 300 Blackout.

The Lancer L5AWM is designed, tooled, manufactured, and assembled in the United States. According to the manufacturer, it’s compatible with modern weapon systems such as the AR-15, SCAR16, HK416, ARX160, SIG556, IWI Tavor, and SA80. It’s ideal for shooters interested in a magazine that lets them visually check capacity without being totally see-through. Please note that the L5AWM is made for heavy duty subsonic 300 BLK, so if you’re using lighter weight loads, you’d be better served with a standard AR-15 magazine.

Lancer Systems L5AWM 300 BLK 30 Magazine Pros and Cons

  • See-through for round count check
  • Ideal for heavy, subsonic 300 BLK
  • Reliable feeding
  • Not great for lighter weight 300 BLK

4 Duramag Speed AR-15 20-round Aluminum Magazine : Best Metal

Duramag Speed AR-15 20-round Aluminum Magazine Featured Image

Duramag Speed AR-15 20-round Aluminum Magazine

An aluminum body USGI style magazine with a 20 round capacity

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  • Reliability A-
  • Features B
  • Fit A-
  • Value B+

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B+

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Duramag Speed AR-15 20-round Aluminum Magazine Specs

  • Capacity 20
  • Weight 3.2 oz
  • Material Aluminum

Duramag Speed AR-15 20-round Aluminum Magazine Review

Although they’re not as popular as they once were, metal magazines remain in common use throughout the gun world. The Duramag Speed AR-15 20-round Aluminum Magazine is a well-made mag with a straightforward design and, as the name states, an aluminum body. It’s designed with the same curved body shape of larger capacity magazines and is a standard AR-15 style. Duramag states the curve of this shorter 20-round capacity model improves feeding, whereas straight-bodied magazines are more prone to failures to feed. They make this magazine for ideal performance in short, light rifles and PDWs (personal defense weapons).

The body of the Duramag Speed AR-15 20-round Aluminum Magazine is robotically welded using 6061-T6 aluminum. It has a Type-III hard-coat anodized finish for superior resistance to wear and durability. The follower is redesigned for anti-tilt functionality and the proprietary Black-T coating is designed for low-friction feeding. According to Duramag, this magazine continues to feed well even when it’s dirty. And because it’s aluminum, it won’t swell or flex like certain polymers can.

Features of this aluminum magazine include a 17-7 stainless steel spring, polymer follower, and steel base plate. It weighs 4 ounces, empty. Duramag offers it with either a black or gray body and an orange or black follower. It’s easy to use a paint pen or Sharpie to mark these aluminum magazines by caliber, if you so choose. This is a great, budget-friendly magazine that works well with most 300 Blackout magazines. 

Duramag Speed AR-15 20-round Aluminum Magazine Pros and Cons

  • Affordably priced
  • Metal body
  • Curved body for consistent feeding
  • Can be more prone to failures

5 Sentry Hexmag AR-15/M4/M16 Replacement Magazine (Series 2) : Best Budget Friendly

Sentry Hexmag AR-15M4M16 Replacement Magazine (Series 2) Featured Image

Sentry Hexmag AR-15/M4/M16 Replacement Magazine (Series 2)

A polymer magazine with a 30 round capacity and a hexagon pattern on the side.

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  • Reliability B+
  • Features B
  • Fit B+
  • Value A-

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B+

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Sentry Hexmag AR-15/M4/M16 Replacement Magazine (Series 2) Specs

  • Capacity 30
  • Weight 4.8 oz
  • Length 7.6 in
  • Material PolyHex2 Advanced Composite

Sentry Hexmag AR-15/M4/M16 Replacement Magazine (Series 2) Review

Although Sentry has changed hands a few times, their magazines continue to be reliable. The Sentry Hexmag AR-15/M4/M16 Replacement Magazine (Series 2) is a good, basic mag that performs well and stands up to pretty hard use. They’re recognizable thanks to the honeycomb—read, hexagon—designs on the body of the magazine, and they come in a variety of colors. They’re lighter in the hand than other polymer brands but still resistant to impacts and crushing. The ridges of the hex design on the exterior of the body provide a good hold during magazines changes. 

They made this magazine to feed consistently. It features redesigned feed lips for this exact reason. And because it’s a Series 2 model, it’s enhanced for even greater performance than the original. Features include a deep catch pocket for stability, a heat-treated, stainless steel spring, and PolyHex2 Advanced Composite body. The Sentry Hexmag AR-15/M4/M16 Replacement Magazine (Series 2) is made using the company’s tool-less design so we can disassemble it as needed for maintenance or swapping out parts as desired. That means it’s fast and easy to utilize the Hexmag HexID Color Ammunition Identification System, so you can clearly mark this magazine for 300 Blackout use.

Sentry is offering this magazine in black, FDE, gray, OD green, and custom HexID colors. It has a 30-round capacity, but there are also magazines available in smaller capacities. Sentry lists this mag as compatible with the AR-15, SCAR16, IWI Tavor, CZ Bren, and Beretta ARX 100, among others. This mag also comes backed by the company’s lifetime guarantee. Hexmags are great all-purpose magazines that are priced to be a little more budget-friendly and can also be customized with various accessories for caliber identification.

Sentry Hexmag AR-15/M4/M16 Replacement Magazine (Series 2) Pros and Cons

  • Lower price-point
  • Customizable by color for caliber identification
  • Feeds reliably
  • Not quite as rugged as other brands

Summary

In the world of firearm accessories, the importance of selecting the right magazine cannot be overstated, especially when dealing with a versatile platform like the AR-15 that supports multiple calibers. For owners of the 300 Blackout, the quest for the ideal magazine goes beyond the mere compatibility – it delves into the nuances of performance, reliability, and purpose-driven design. Our exploration into the realm of 300 Blackout magazines has sought to simplify this often-overlooked aspect of firearm ownership.

The necessity of having dedicated 300 Blackout magazines, as opposed to relying on generic AR-15 counterparts, becomes evident when considering the potential risks associated with cross-caliber mixing. Catastrophic failures can arise, and to mitigate such risks, having magazines specifically tailored for the 300 Blackout is not just a luxury but a prudent choice. Understanding the anatomy of these magazines, including components such as the body, spring, follower, and floor plate, underscores the importance of precision engineering to meet the unique demands of the 300 Blackout cartridge.

Our curated selection of the best 300 Blackout magazines aims to alleviate the guesswork, offering a diverse range of options to cater to various preferences and shooting styles. From the battle-proven durability of the Magpul PMAG 30 AR 300 B Gen M3 to the transparency and precision engineering of the Lancer Systems L5AWM, each magazine on our list has been chosen for its distinctive features and capabilities. These magazines are not mere accessories; they are purpose-built tools designed to enhance the performance of your AR-15 chambered in 300 Blackout.

As shooters embark on the quest to find their ideal 300 Blackout magazine, it’s crucial to consider factors such as reliable feeding, durability under stress, and clear caliber markings. The magazine is not just a container for cartridges; it is a critical component that can significantly impact the overall functionality and reliability of your firearm. Our reviews aim to guide users through these considerations, offering insights into the performance, strengths, and potential drawbacks of each selected magazine.

Conclusion

In conclusion, the journey to discover the best 300 Blackout magazine involves more than a mere transaction; it’s a quest for precision, reliability, and confidence in your equipment. Whether you prioritize the battle-ready reliability of the Magpul PMAG, the duty-ready enhancements of the Amend2 Mod-3, the transparency of the Lancer Systems L5AWM, the metal-body reliability of the Duramag Speed, or the budget-friendly functionality of the Sentry Hexmag Series 2 – each choice reflects a commitment to optimizing your AR-15 for 300 Blackout performance. So, embark on your exploration armed with knowledge, and may your shooting experience be defined by accuracy, consistency, and the satisfaction of a well-chosen magazine.

Frequently Asked Questions

Why do I need a dedicated 300 Blackout magazine?

While standard AR-15 magazines may work, having a dedicated 300 Blackout magazine ensures optimal performance and reduces the risk of catastrophic failures. The specific design and markings help avoid errors.

Are all AR-15 magazines suitable for 300 Blackout?

Not necessarily. Not all magazines perform equally across different firearms. It’s important to test and find magazines that reliably feed 300 Blackout rounds. Trial and error may be involved.

What features should I consider when choosing a 300 Blackout magazine?

Key considerations include reliable feeding, durability, clear markings for caliber identification, and a long spring and function life. Additionally, the magazine’s ability to withstand rough handling is crucial.

How can I differentiate between magazines for 223 Remington and 300 Blackout?

Look for specific markings on the magazine body. For instance, Magpul’s PMAG 30 AR 300 B Gen M3 has a distinct rib design on the lower half and is marked “300 BLK.” Transparent magazines like Lancer Systems’ L5AWM also have large “300 BLK” markings.

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About Kat Ainsworth-Stevens

Kat is a respected author and dedicated student of the gun. To date, she has published three books and written thousands of articles on firearms and self-defense in print and online.

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